The purpose of this exercise is to make you familiar with the Autocode platform.Estimated workload of this exercise is5 minutes.

Please, proceed toHelloAutocode classand write a simple program that prints "Hello, Autocode!" (don't print quote marks).

The purpose of this exercise is to familiarize you with basic usage of standard input stream.

Estimated workload of this exercise is5 minutes.

Please, proceed to the classMeetAStranger.The program must read a string from System.in and print a message "Hello,input".

Note that when entering an input string consisting of several words, the entire input must be printed.

Input:Mrs. Robinson

Output:Hello, Mrs. Robinson

The purpose of this exercise is to familiarize you with basicint operations.

Estimated workload of this exercise is30 minutes.

Please, proceed toElectronicWatch class.The program must print an electronic watch screen output for a given value of seconds since midnight.

Input value is given viaSystem.in. Output value must be printed toSystem.out

It is guaranteed, that input number is non-negative.

Output format ish:mm:ss (possible values: [0:00:00; 23:59:59]).

Extra challenge: try to solve the task without usingif statements or cycles.

Input:60

Output:0:01:00

Input:3599

Output:0:59:59

Input:86229

Output:23:57:09

Input:86400

Output:0:00:00

Input:89999

Output:0:59:59

Input:86460

Output:0:01:00

The purpose of this exercise is to familiarize you with simple conditional statements.

Estimated workload of this exercise is20 min.

Please, proceed toMeetAnAgent classand write a program that:

• asks for an input number,
• if the input equals to the secret password number, prints "Hello, Agent",
• otherwise, prints "Access denied"

Secret password is stored infinal static int PASSWORD.

Input:133976

Output:Hello, Agent

Input:711

Output:Access denied

The purpose of this exercise is to train you in usage of simple cycles and conditional statements.

Estimated workload of this exercise is20 min.

Please, proceed toHelloStrangers classand write a program that:

• asks for a number - amount of strangers to meet,
• then reads stranger names line by line
• and, finally, prints line by line "Hello,stranger name" for each stranger.

It is guaranteed that the input is not null.It is guaranteed that the input of strangers count is int number.

Consider special cases:

• If strangers count is zero, then program must print "Oh, it looks like there is no one here".
• If strangers count is negative, then program must print "Seriously? Why so negative?".

Hint: In case you use the Scanner class, it might be helpful sure to check strings it reads be non-empty.

Input:

3AthosPorthosAramis

Output:

Hello, AthosHello, PorthosHello, Aramis

Input:

0

Output:

Oh, it looks like there is no one here

Input:

-3

Output:

Seriously? Why so negative?

The purpose of this exercise is to train you in usage of simple integer operations.

Estimated workload of this exercise is30 min.

Consider a snail travels up a treea feet each day. Then snail slides downb feet each night. Height of the tree ish feet.

Please, proceed toSnail classand write a program that prints number of days for the snail to reach the top of the tree.

Program readsa,b,h line by line. Input values are guaranteed to be positive integers.

If the snail cannot reach the top of the tree, print the messageImpossible.

Input:

4214

Output:

6

Input:

4310

Output:

7

Input:

4410

Output:

Impossible

Input:

441

Output:

1

The purpose of this exercise is to familiarize you with basic conditional and cyclic operations.

Estimated workload of this exercise is20 minutes.

Consider a company of friends visiting a restaurant.They decided to equally split the bill.

Friends decided to add 10 percent of the bill total amount as tips.Then they cover the total payment in equal parts.

Please, proceed toGoDutch classand write a program that reads a bill total amount and a number of friends, and then prints part to pay.

Consider some details:

• Program must read data from System.in
• Bill total amount cannot be negative. If input value is negative, the program stops, printing:Bill total amount cannot be negative
• Number of friends cannot be negative or zero. If input value is, then the program stops, printing:Number of friends cannot be negative or zero
• Bill total amount, number of friends and part to pay are integers

Input:

1000  5

Output:

220

The purpose of this exercise is to train you to use simple loops and conditional statements.

Estimated workload of this exercise is20 min.

Please, proceed toFindMaxInSeqand write a program that reads a sequence of integer values from standard output and finds the maximum value. You mustplace your solution into themax method to pass tests.

Details:

• You must read sequence values until the next one is0. Zero value means end of the input sequence.
• The sequence is guaranteed to contain at least one value.

Input:

2 4 6 9 2 4 5 0

Output:

9

The purpose of this exercise is to train you to use simple loops and conditional statements.

Estimated workload of this exercise is20 min.

Please, proceed toAverage classand write a program that reads a sequence of integer values from standard input and finds the average value.

Details:

• You must read sequence values until the next one is0. Zero value means end of the input sequence.
• The sequence is guaranteed to contain at least one value.
• Average value is also aninteger. Useinteger operations.

Input:1 2 3 4 5 0

Output:3

Input:1 2 3 4 6 0

Output:3

Input:1 2 3 4 0

Output:2

Input:1 1 9 0

Output:3

The purpose of this exercise is to familiarize you with basic conditional and cyclic operations.

Estimated workload of this exercise is20 minutes.

Please, proceed toPizzaSplit class.The program must read two values fromSystem.in:

• number of people;
• number of pieces per pizza.

It is guaranteed that this values are positive integers.

Then the program must print the minimum number of pizzas (not zero) so that everyone has an equal number of slices and no slice is left.

Input:12 8

Output:3

The purpose of this exercise is to train you to design programs that need decision trees.

Estimated workload of this exercise is30 min.

Please, proceed to theQuadraticEquation class and implement a program to solve quadratic equations.

For the given quadratic equation coefficients (ax² + bx + c = 0),return one or two roots of the equation if there is any in the set of real numbers.

Input value is given viaSystem.in. Output value must be printed toSystem.out.

Output format is:

• "x₁ x₂" (two roots in any order separated by space) if there are two roots,
• "x" (just the value of the root) if there is the only root,
• "no roots" (just a string value "no roots") if there is no root.

Thea parameter is guaranteed to be not zero.

Hint:Quadratic formula reference

Input:1 -2 1

Output:1

Input:2 5 -3

Output:-3 0.5

Input:2 2 2

Output:no roots

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is20 min.

Please, proceed to theMaxMethod classand implement themax method.

The correct implementation should receive an array ofint values and return its maximum value.

Details:

• An input array is guaranteed to not be an empty array ornull.
• max method must not modify the array.
• Input array may contain anyint value betweenInteger.MIN_VALUE andInteger.MAX_VALUE.

int[]vals =newint[]{-2,0,10,5};intresult =MaxMethod.max(vals);System.out.println(result ==10);// true

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is20 min.

Please, proceed to theSumOfEvenNumbers class andimplement thesum method.

The correct implementation should receive an array ofint values and return the sum of even numbers.

Details:

• If given array is null or empty, method returns 0.
• sum method must not modify the array.
• Input array may contain anyint value betweenInteger.MIN_VALUE andInteger.MAX_VALUE.

int[]vals =newint[]{-2,10,0,5};intresult =SumOfEvenNumbers.sum(vals);System.out.println(result ==8);// true

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is20 min.

Please, proceed toSumOfPrevious classand implementgetSumCheckArray method.

The correct implementation should receive an array ofint valuesand return an array of booleans where each element is a resultof a check if a corresponding element is a sumof two previous elements in given array.

Details:

• The length of given array is guaranteed to be 2 or more.
• Given array is guaranteed to be not null.
• Method returns an array of booleans where each element is a result for corresponding element in given array.
• First two elements of the boolean array are always false.

Input array:[1, -1, 0, 4, 6, 10, 15, 25]

Output array:[false, false, true, false, false, true, false, true]

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is30 min.

Please, proceed to theLocalMaximaRemove class andimplement theremoveLocalMaxima method.

The correct implementation should receive an array ofint valuesand return a copy of a given array with all local maxima removed in it.The original array must not be changed.

Local maximum is an element that is bigger that any of its neighbour elements.You should remove elements that are local maxima in the original array.

Details:

• The size of given array is guaranteed to be more than 1.
• Given array is guaranteed to be not null.
• If the array has no local maxima, then you should return its copy without changes.
• You may use java.util.Arrays.* methods.

Input array:[18, 1, 3, 6, 7, -5]

Output array:[1, 3, 6, -5]

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is30 min.

Please, proceed toCycleSwap classand implement its static methods:

• void cycleSwap(int[] array)
  Shifts all the elements in the given array to the right by 1 position.
  In this case, the last array element becomes first.
  For example,1 3 2 7 4 becomes4 1 3 2 7.

• void cycleSwap(int[] array, int shift)
  Shift all the elements in the given array to the right in the cycle manner byshift positions.
  Shift value is guaranteed to be non-negative and not bigger than the array length.
  For example,1 3 2 7 4 with a shift of3 becomes2 7 4 1 3.

For a greater challenge, try not using loops in your code (not mandatory).

Note that input array may be empty.

Code Sample:

...int[]array =newint[]{1,3,2,7,4};CycleSwap.cycleSwap(array);System.out.println(Arrays.toString(array));

Output:

[4, 1, 3, 2, 7]

Code Sample:

...int[]array =newint[]{1,3,2,7,4};CycleSwap.cycleSwap(array,2);System.out.println(Arrays.toString(array));

Output:

[7, 4, 1, 3, 2]

Code Sample:

...int[]array =newint[]{1,3,2,7,4};CycleSwap.cycleSwap(array,5);System.out.println(Arrays.toString(array));

Output:

[1, 3, 2, 7, 4]

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is45 min.

Please, proceed toSpiral class and implement its static method:

• int[][] spiral(int rows, int columns)
  Return a two-dimensional array coming in the form of a table and containing numbers from1 up torows * columns. The size of the table will be specified by the given parameters.
  Numbers fill the "table" clockwise from the top-level corner in a spiral manner.
  For example, for parameter values(3, 4), the output array should be:

   1  2  3  410 11 12  5 9  8  7  6

Code Sample:

...int[][]spiral =Spiral.spiral(3,4);for (inti =0;i <spiral.length;i++) {for (intj =0;j <spiral[i].length;j++) {System.out.print(String.format("%4s",spiral[i][j]));    }System.out.println();}

Output:

   1   2   3   4  10  11  12   5   9   8   7   6

Code Sample:

...int[][]spiral =Spiral.spiral(4,3);for (inti =0;i <spiral.length;i++) {for (intj =0;j <spiral[i].length;j++) {System.out.print(String.format("%4s",spiral[i][j]));    }System.out.println();}

Output:

   1   2   3  10  11   4   9  12   5   8   7   6

Code Sample:

...int[][]spiral =Spiral.spiral(5,6);for (inti =0;i <spiral.length;i++) {for (intj =0;j <spiral[i].length;j++) {System.out.print(String.format("%4s",spiral[i][j]));    }System.out.println();}

Output:

   1   2   3   4   5   6  18  19  20  21  22   7  17  28  29  30  23   8  16  27  26  25  24   9  15  14  13  12  11  10

Code Sample:

...int[][]spiral =Spiral.spiral(5,5);for (inti =0;i <spiral.length;i++) {for (intj =0;j <spiral[i].length;j++) {System.out.print(String.format("%4s",spiral[i][j]));    }System.out.println();}

Output:

   1   2   3   4   5  16  17  18  19   6  15  24  25  20   7  14  23  22  21   8  13  12  11  10   9

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is45 min.

Please, proceed toTransposeMatrixclass an implement its methodmultiply.

It takes a rectangular integer array (matrix) as a parameter and returns it transposed.

Consider an integer matrix represented as arectangular array.The task is totranspose a given matrix over its main diagonal.Thetransposition of a matrix over its main diagonal is simply a flipped version of the original matrix.

Hint:Transpose Reference

Input:

  {     {0, 1, 2},      {3, 4, 5},      {6, 7, 8}  }

Output:

  {     {0, 3, 6},      {1, 4, 7},      {2, 5, 8}  }

The purpose of this exercise is to train you to work with arrays.

Estimated workload of this exercise is60 min.

Please, proceed toMultiplyMatrixclass and implement itsmultiply method.

It takes two rectangular integer arrays (matrices) and returns the result of their multiplication.

Consider two integer matrices represented asrectangular arrays. The task is tomultiply given matrices. Thedefinition ofmatrix multiplication indicates a row-by-column multiplication,where the entries in thei-th row ofAare multiplied by the corresponding entries in thej-th column ofBand then theij-th element of the resulting matrix is the sum of that multiplication results.

Note that it is guaranteed thatthe number of columns in the first matrixis equal to the number of rows in the second matrix.

Input:

    {{1, 2, 3},     {4, 5, 6}},         {{7 , 8 },     {9 , 10},    {11, 12}}

Output:

    {{58 , 64 },    {139, 154}}

The purpose of this exercise is to train you to work with classes and methods.

Estimated workload of this exercise is45 min.

Please, implement the methodintersection(Line) in classLine.It must return aPoint of intersection of two lines.

Note that lines are defined by linear equations:y = k * x + b.Line constructor takesk andb coefficients as parameters.

If lines coincide or do not intersect, the method must return null.It may seem surprising that we useint for arguments and fields of coordinates.The point is that usingdouble will bring some extra complexity we want to avoid for this basic exercise.All tests are selected in to induce calculations without remainders.

You may check your result in classMain.

publicclassMain {publicstaticvoidmain(String[]args) {Lineline1 =newLine(1,1);Lineline2 =newLine(-1,3);System.out.println(line1.intersection(line2));// (1;2)    }}

The purpose of this exercise is to train you to work with classes and methods.

Estimated workload of this exercise is45 min.

Please, implement the following methods of classSegment:

• constructor with start and end points as parameters
  Ensure that a created segment exists and is not degenerativewhich means that the start and the end of the segment is not the same point.
  If it is, usethrow new IllegalArgumentException() to raise an error.
• double length()
  Return length of the segment.
• Point middle()
  Return a middle point of the segment.
• Point intersection(Segment another)
  Return a point of the intersection of the current segment and the given one.
  Returnnull if there is no such point.
  Returnnull if segments are collinear.
  Please, note that intersection point must lay on both segments.

ClassPoint is already there.

Hints:

• Length reference
• Midpoint reference
• Intersection reference

You may useMain class to try your code.There are some examples below.

Sample code:

...doublelength =newSegment(newPoint(0,0),newPoint(3,4)).length();System.out.println(length);

Output:5

Sample code:

...Segmentfirst =newSegment(newPoint(0,0),newPoint(4,4));Segmentsecond =newSegment(newPoint(2,0),newPoint(0,2));Pointintersection =first.intersection(second);System.out.println(intersection.getX());System.out.println(intersection.getY());

Output:

11

Sample code:

...Segmentsegment =newSegment(newPoint(2,0),newPoint(0,2));Pointmidpoint =segment.middle();System.out.println(midpoint.getX());System.out.println(midpoint.getY());

Output:

11

Sample code:

...Segmentfirst =newSegment(newPoint(0,0),newPoint(4,0));Segmentsecond =newSegment(newPoint(2,1),newPoint(1,2));Pointintersection =first.intersection(second);System.out.println(intersection ==null);

Output:

true

The purpose of this exercise is to train you to work with classes and methods.

Estimated workload of this exercise is45 min.

Please, implement methods of classTriangle:

• constructor, which has three points as parameters.
  Consider these points as vertices of the triangle.
  Ensure that the created triangle exists, and it is not degenerative.
  If it is, usethrow new IllegalArgumentException() to raise an error.
• double area()
  Return the area of the triangle.
• Point centroid()
  Return the centroid of the triangle.

ClassPoint is already there.

Hints:

• Triangle existence reference
• Triangle area reference
• Centroid reference

Please note that you may benefit from introducing more classes.

Sample code:

...newTriangle(newPoint(0,0),newPoint(1,0),newPoint(2,0));

Result: Exception because such a triangle would be degenerative.

Sample code:

...doublearea =newTriangle(newPoint(0,0),newPoint(3,0),newPoint(0,4)).area();System.out.println(area);

Output:

6

Sample code:

...Pointcentroid =newTriangle(newPoint(0,0),newPoint(3,0),newPoint(0,3)).centroid();System.out.println(centroid.getX());System.out.println(centroid.getY());

Output:

11

The purpose of this exercise is to train you designing simple classes and their relations.

Estimated workload of this exercise is2h.

Decrementing Carousel is a container, acceptingint elements.DecrementingCarousel has a maximum capacity, specified via the constructor.When created,DecrementingCarousel is in accumulating state: you may add elements via theaddElement method and can produce aCarouselRun object via therun method.Once therun method is called,DecrementingCarousel is in running state: it refuses adding more elements.

TheCarouselRun allows to iterate over elements of the carousel decrementing them one by one with thenext method.Thenext returns the value of the current element:

Then it decreases the current element by one and switches to the next element:

TheCarouselRun iterates over elements in the order of their insertion.
When an element is decreased to zero, theCarouselRun will skip it in further iterations.When there are no more elements available for decrementing, theCarouselRun returns-1.

TheCarouselRun also has theisFinished method, which indicates, if the carousel has run out of the elements to decrement.

DecrementingCarousel has two public methods:

• boolean addElement(int element) - adds an element.If element is negative or zero, do not add the element.If container is full, do not add the element.If therun method was called to create aCarouselRun, do not add the element.If element is added successfully, returntrue. Returnfalse otherwise.
• CarouselRun run() - returns aCarouselRun to iterate over the elements.If therun method has already been called earlier, it must returnnull:DecrementingCarousel may generate only oneCarouselRun object.

CarouselRun has two public methods:

• int next() - returns the current value of the current element,then decreases the current element by one and switches to the next element in insertion order.Skips zero elements. When there is no more elements to decrease, returns-1.
• boolean isFinished() - when there is no more elements to decrease, returnstrue. Otherwise, returnsfalse.

Empty case:

CarouselRunrun =newDecrementingCarousel(7).run();System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Regular case:

DecrementingCarouselcarousel =newDecrementingCarousel(7);carousel.addElement(2);carousel.addElement(3);carousel.addElement(1);CarouselRunrun =carousel.run();System.out.println(run.isFinished());//falseSystem.out.println(run.next());//2System.out.println(run.next());//3System.out.println(run.next());//1System.out.println(run.next());//1System.out.println(run.next());//2System.out.println(run.next());//1System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Refusing adding more elements case:

DecrementingCarouselcarousel =newDecrementingCarousel(3);System.out.println(carousel.addElement(-2));//falseSystem.out.println(carousel.addElement(0));//falseSystem.out.println(carousel.addElement(2));//trueSystem.out.println(carousel.addElement(3));//trueSystem.out.println(carousel.addElement(1));//true//carousel is fullSystem.out.println(carousel.addElement(2));//falseCarouselRunrun =carousel.run();System.out.println(run.next());//2System.out.println(run.next());//3System.out.println(run.next());//1System.out.println(run.next());//1System.out.println(run.next());//2System.out.println(run.next());//1System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Refusing to add more elements after "run" was called:

DecrementingCarouselcarousel =newDecrementingCarousel(10);System.out.println(carousel.addElement(2));//trueSystem.out.println(carousel.addElement(3));//trueSystem.out.println(carousel.addElement(1));//truecarousel.run();System.out.println(carousel.addElement(2));//falseSystem.out.println(carousel.addElement(3));//falseSystem.out.println(carousel.addElement(1));//false

Refusing to create more than one CarouselRun:

DecrementingCarouselcarousel =newDecrementingCarousel(10);System.out.println(carousel.run() ==null);//falseSystem.out.println(carousel.run() ==null);//true

The purpose of this exercise is to train you to use extend classes withextends keyword.

Estimated workload of this exercise is30 min.

Note, that if you have not done the "Decrementing Carousel" exercise,you have to implementDecrementingCarousel andCarouselRun classes.

In this exercise you need to extendDecrementingCarousel.You need to implementHalvingCarousel.This subclass must halve elements instead of decrementing it by one.Note that you need to apply regular integer division, discarding the remainder.For example,5 / 2 = 2.

Empty case:

CarouselRunrun =newHalvingCarousel(7).run();System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Regular case:

DecrementingCarouselcarousel =newHalvingCarousel(7);carousel.addElement(20);carousel.addElement(30);carousel.addElement(10);CarouselRunrun =carousel.run();System.out.println(run.isFinished());//falseSystem.out.println(run.next());//20System.out.println(run.next());//30System.out.println(run.next());//10System.out.println(run.next());//10System.out.println(run.next());//15System.out.println(run.next());//5System.out.println(run.next());//5System.out.println(run.next());//7System.out.println(run.next());//2System.out.println(run.next());//2System.out.println(run.next());//3System.out.println(run.next());//1System.out.println(run.next());//1System.out.println(run.next());//1System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

The purpose of this exercise is to train you to use extend classes withextends keyword.

Estimated workload of this exercise is30 min.

Note, that if you have not done the "Decrementing Carousel" exercise,you have to implementDecrementingCarousel andCarouselRun classes.

In this exercise you need to extendDecrementingCarousel.You need to implementGraduallyDecreasingCarousel.This subclass must decrement elements by gradually increasing decrement.When you need to decrement an element for the first time, decrease it by1.Next time you need to decrement the same element, decrease it by2.Next time decrease by3, then by4 and so on.Remember that you must not make process non-positive elements.

Empty case:

CarouselRunrun =newGraduallyDecreasingCarousel(7).run();System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Regular case:

DecrementingCarouselcarousel =newGraduallyDecreasingCarousel(7);carousel.addElement(20);carousel.addElement(30);carousel.addElement(10);CarouselRunrun =carousel.run();System.out.println(run.isFinished());//falseSystem.out.println(run.next());//20System.out.println(run.next());//30System.out.println(run.next());//10System.out.println(run.next());//19System.out.println(run.next());//29System.out.println(run.next());//9System.out.println(run.next());//17System.out.println(run.next());//27System.out.println(run.next());//7System.out.println(run.next());//14System.out.println(run.next());//24System.out.println(run.next());//4System.out.println(run.next());//10System.out.println(run.next());//20System.out.println(run.next());//5System.out.println(run.next());//15System.out.println(run.next());//9System.out.println(run.next());//2System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

The purpose of this exercise is to train you to use extend classes withextends keyword.

Estimated workload of this exercise is30 min.

Note, that if you have not done the "Decrementing Carousel" exercise,you have to implementDecrementingCarousel andCarouselRun classes.

In this exercise you need to extendDecrementingCarousel.You need to implementDecrementingCarouselWithLimitedRun.This subclass must decrement elements as a usual DecrementingCarousel.The difference is that this implementation must produce a carousel run,which limits number of calls to thenext method.When the limit of calls reached carousel run must consider itself finished.

Empty case:

CarouselRunrun =newDecrementingCarouselWithLimitedRun(7,5).run();System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

Regular case:

DecrementingCarouselcarousel =newDecrementingCarouselWithLimitedRun(7,10);carousel.addElement(20);carousel.addElement(30);carousel.addElement(10);CarouselRunrun =carousel.run();System.out.println(run.isFinished());//falseSystem.out.println(run.next());//20System.out.println(run.next());//30System.out.println(run.next());//10System.out.println(run.next());//19System.out.println(run.next());//29System.out.println(run.next());//9System.out.println(run.next());//18System.out.println(run.next());//28System.out.println(run.next());//8System.out.println(run.next());//17System.out.println(run.isFinished());//trueSystem.out.println(run.next());//-1

The purpose of this exercise is to train basic inheritance features.

Estimated workload of this exercise is120 min.

In this exercise we are going to manage business logic of planning a sprint.A sprint is the basic unit of software development in SCRUM.Sprints are time boxed. Time capacity of a sprint is agreed while planning.Then we consider a sprint to be filled with some tasks.

We consider a task to be implemented with general-purposeTicket class.But we also consider a sprint to accept only subtypes of theTicket class:Bug andUserStory.

Here is a diagram depicting the public interface of these classes and their relations:

Here are API details:

• Ticket
  Every ticket has an id, a name and an estimate of hours to complete it.One provides them via the constructor of theTicket class.Also, a ticket may be completed or not. When a ticket is created, it is not completed.
  • getId() - Returns the id of the ticket.
  • getName() - Returns the name of the ticket.
  • getEstimate() - Returns the estimate of the ticket.
  • isCompleted() - Returnstrue if the ticket is completed,false otherwise.
  • complete() - Sets the ticket to completed state.
• UserStory
  We consider a user story to be a ticket that may contain some dependencies.A dependency is another user story that must be completed first to allow the dependent user story to complete.One provides dependencies of the UserStory via the constructor of theUserStory class.
  • complete() - Like theTicket#complete() method, this sets the ticket to completed state.The difference is that the user story may not be completed if its dependencies are not completed yet.
  • getDependencies() - Returns a defensive copy of dependencies array.
  • toString() - Returns a String representing this user story, using its id and name.Example: "[US 1] User Registration Entity"
• Bug
  We consider a bug to be a ticket, that is related to some completed user story.Bugs may not exist by their on, without a related user story.
  • createBug(int id, String name, int estimate, UserStory userStory) - A static method to create a Bug instance.
    Returnsnull if the related user story isnull or is not completed. Otherwise, returns a created Bug instance.
  • toString() - Returns a String representing this bug, using its id, name and the name of the related user story.
    Example: with id = 2, name = "Add password repeat" and the related user story name = "Registration Form"the resulting string would be "[Bug 2] Registration Form: Add password repeat"
• Sprint
  Sprints has the time capacity and the tickets limit, specified via constructor.It is not allowed for a Sprint to contain tickets with total estimate greater than time capacity.It is not allowed for a Sprint to contain total amount of tickets greater than tickets limit.
  We consider a sprint to accept tickets viaadd* methods.That methods returntrue when an input ticket was accepted andfalse otherwise.Note that we consider a sprint to not accept:
  1. null values,
  2. tickets, that are already completed
  3. tickets, that has an estimate value that will lead to capacity overflow if added
  4. any ticket, if the sprint ticket limit is reached.
  • addUserStory(UserStory userStory) - accepts a userStory, if it is notnull, not completedand its uncompleted dependencies are already accepted to the sprint.Returnstrue if the user story is accepted,false otherwise.
  • addBug(Bug bugReport) - accepts a bug, if it is notnull and not completed.Returnstrue if the bug is accepted,false otherwise.
  • getTickets() - Returns a defensive copy of the array of the sprint tickets.Make sure the order of tickets is as they were accepted to the sprint.
  • getTotalEstimate() - Returns the sum of estimates of all the tickets accepted to the sprint.

Important restriction: Note that in this exercise youmay not useCollections andStreams.

Wikipedia on the Scrum Sprint:https://en.wikipedia.org/wiki/Scrum_(software_development)#Sprint

The purpose of this exercise is to train you designing simple interface implementations and use them.

Estimated workload of this exercise is2h.

In this exercise you need to design two implementations of theTask interface:

• CountDownTask:
  • The constructor ofCountDownTask takes a single int value as a parameter.It is the initial value of the countdown.Input value must not be negative. If it is, set zero value.
  • Each time theexecute method is called, this value decrements by one, until it reaches zero.Then theexecute method no longer decrements the value and the task is considered finished.
  • If the task is initialized with zero value, consider it finished right upon creating.
  • Value of the task is accessible via getter.
• CompleteByRequestTask:
  • Constructor of theCompleteByRequestTask takes no parameters.
  • Callingexecute method on the task does not make it finished until thecomplete method is called.
  • Once thecomplete method is called, the next call toexecute makes the task finished.Note that the task is not finished right after calling thecomplete method.The task finishesonly when subsequent call toexecute occurs.

Also, you need to implement theTaskCarousel:

• A task carousel has a capacity provided as a constructor parameter.
• TheTaskCarousel hasisEmpty method.It returnstrue if there is no task in the carousel for execution.Returnsfalse otherwise.
• TheTaskCarousel hasisFull method.It returnstrue if there is no more room in the carousel to add another task.Returnsfalse otherwise.
• You may add tasks to the carousel viaaddTask method. It returnstrue if the task is accepted andfalse otherwise.Task may be not accepted due to following reasons:
  • Task argument is null.
  • Task is already finished.
  • Carousel is full.
• You may execute tasks in the carousel viaexecute method.
  • Each time when this method is invoked, carousel must switch to the next task within and execute it.
  • Iteration is in circular manner.If there are 4 tasks inside a carousel,then if we callexecute method on the carousel 4 times in a row,each task must be executed once.
  • If the task is finished after execution, remove it from the carousel.
  • The method returnstrue if any task was executed. Returnsfalse otherwise.

Single task case:

TaskCarouselcarousel =newTaskCarousel(4);System.out.println(carousel.isEmpty());//trueSystem.out.println(carousel.isFull());//falseSystem.out.println(carousel.execute());//falseCountDownTasktask =newCountDownTask(2);System.out.println(carousel.addTask(task));//trueSystem.out.println(carousel.isEmpty());//falseSystem.out.println(carousel.isFull());// falseSystem.out.println(task.getValue());//2System.out.println(carousel.execute());//trueSystem.out.println(task.getValue());//1System.out.println(carousel.execute());//trueSystem.out.println(task.getValue());//0System.out.println(carousel.execute());//falseSystem.out.println(carousel.isEmpty());//true

Three tasks case:

TaskCarouselcarousel =newTaskCarousel(3);CountDownTasktask1 =newCountDownTask(2);CountDownTasktask2 =newCountDownTask(2);CompleteByRequestTasktask3 =newCompleteByRequestTask();System.out.println(carousel.addTask(task1));//trueSystem.out.println(carousel.addTask(task2));//trueSystem.out.println(carousel.addTask(task3));//trueSystem.out.println(carousel.isFull());// truefor(inti =0;i <100;i++){System.out.println(carousel.execute());// true}System.out.println(task1.isFinished());// trueSystem.out.println(task2.isFinished());// trueSystem.out.println(task3.isFinished());// falsetask3.complete();System.out.println(task3.isFinished());// falseSystem.out.println(carousel.execute());// trueSystem.out.println(task3.isFinished());// trueSystem.out.println(carousel.isEmpty());// true

The purpose of this exercise is to train you to work with classes, methods and inheritance.

Estimated workload of this exercise is60 min.

Please, makeTriangle,Quadrilateral,Circle classesextendFigure abstract class.

Implement methods inTriangle,Quadrilateral,Circle:

1. constructors with following parameters:

• Triangle - three vertices (points) as parameters.
• Quadrilateral - four vertices (points) as parameters.
• Circle - point of the center anddouble value of the radius.

All the input datasets in tests are guaranteed to form a non-degenerative figures.For Quadrilaterals, it is guaranteed that all test datasets would form a convex quadrilaterals.

2. public double area()
   Return the area of the figure.
   Note: Convex quadrilaterals can be divided into two triangles by any of their diagonals.

3. public String pointsToString()
   Return a String value in following formats:

• Triangle -
  • Format:(a.x,a.y)(b.x,b.y)(c.x,c.y)
  • Example:(0.0,0.0)(0.1,5.8)(7.0,7.0)
• Quadrilateral -
  • Format:(a.x,a.y)(b.x,b.y)(c.x,c.y)(d.x, d.y)
  • Example:(0.0,0.0)(0.0,7.1)(7.0,7.0)(7.0,0.0)
• Circle -
  • Format:(center.x,center.y)
  • Example:(0.0,0.6)

Note:: you may benefit from implementing toString() in thePoint class

4. public String toString()
   Return a String value in following formats:

• Triangle -
  • Format:Triangle[(a.x,a.y)(b.x,b.y)(c.x,c.y)]
  • Example:Triangle[(0.0,0.0)(0.1,5.8)(7.0,7.0)]
• Quadrilateral -
  • Format:Quadrilateral[(a.x,a.y)(b.x,b.y)(c.x,c.y)(d.x, d.y)]
  • Example:Quadrilateral[(0.0,0.0)(0.0,7.1)(7.0,7.0)(7.0,0.0)]
• Circle -
  • Format:Circle[(center.x,center.y)radius]
  • Example:Circle[(0.0,0.6)4.5]

Note: you may use default implementation given in theFigure class, when it suits a case well.

5. public Point leftmostPoint()
   Return a leftmost point of the figure: the one having the leastX coordinate.
   If there are many leftmost points, return any of them.

Point class is already there.

Hints:

• Degeneracy reference
• Convex quadrilateral reference
• Triangle area reference
• Circle area reference
• Quadrilateral area reference

You may useMain class to try your code.There are some examples below.

Sample code:

...doublearea =newTriangle(newPoint(0,0),newPoint(3,0),newPoint(0,4)).area();System.out.println(area);

Output:

6

Sample code:

...doublearea =newQuarilateral(newPoint(1,0),newPoint(2,1),newPoint(1,2),newPoint(0,1)).area();System.out.println(area);

Output:

2

Sample code:

...doublearea =newCircle(newPoint(1,1),3).area();System.out.println(area);

Output:

28.274333882308138

The purpose of this exercise is to train you to work with classes, methods and inheritance.

Estimated workload of this exercise is60 min.

Please, makeTriangle,Quadrilateral,Circle classesextendFigure abstract class.

Implement methods inTriangle,Quadrilateral,Circle:

1. Constructors with following parameters:

• Triangle - three vertices (points) as parameters.

• Quadrilateral - four vertices (points) as parameters.

• Circle - point of the center and double value of the radius.

  Ensure figures are not degenerative.
  All of them must have non-zero area.
  Quadrilateral is also must be convex.
  If a figure is not good, throw an IllegalArgumentException.
  Note: A non-degenerative convex quadrilateral is divided into four non-degenerative triangles by its diagonals.Note: double calculations are not completely accurate, useerror delta, where applies.

2. public Point centroid()
   Return the centroid of the figure.
   Centroid refers to center of mass of the plain figure, not the baricenter.
   In other words it should be"area centroid".
3. public boolean isTheSame(Figure figure)
   Two figures are considered to be the same only:

• if they have the same type

• and if they coincide (e.g. have same vertices).

  Note: order of the vertices have not to be the same.
  Note: double calculations are not completely accurate, useerror delta, where applies.

Note for curious: it is almost likeequals() but it is not. Methodequals requires consistent behavior alongsidehashCode() and it is quite complicated to establish in terms of approximate equality like in this exercise

Point class is already there.

You may usemain method ofFigure class to try out your code.

Hints:

• Degeneracy reference
• Convex quadrilateral reference
• Circle centroid reference
• Triangle centroid reference
• Quadrilateral centroid reference
• Quadrilateral centroid reference 2

The purpose of this exercise is to train using nested classes.

Estimated workload of this exercise is60 min.

In this exercise we are going to manage contacts information.

AContact is a class containingdifferent information of how to reach a person or a company: phone number, emails, social media.

A contact has a name, which is provided via the class constructor.Also, a contact contains limited amount of entries:

• a phone number (only a single one)
• emails (up to 3 entries)
• social media links (up to 5 entries)

A contact info entry is described withContactInfo interface.Each entry has a title and a value.You need to implemented them as nested classes of theContact class:

• Contact.NameContactInfo - AContactInfo implementation providing the name of the contact.Implement as private non-static nested class. Use"Name" for the entry title.It must not have its own fields. It must use fields of the boundedContact instance instead.
• Contact.Email - AContactInfo implementation containing an email.Implement as public static nested class. Use"Email" for the entry title.
• Contact.Social - AContactInfo implementation containing a social media link/id.Implement as public static nested class. Let the user of the class define the title.
• Other implementations must be anonymous. Do not provide other non-anonymous classes.

It is possible to add contact info entries viaadd* methods.All such methods return the created entry as the result,null if nothing was added to the contact.

• addEmail(String localPart, String domain)
  Adds an email entry.
  addEmail("someone", "somewhere.com").getValue() will result tosomeone@somewhere.com.
• addEpamEmail(String firstname, String lastname)
  Adds a special email entry with "epam.com" domain.Please, implement this method using an anonymous extension of theEmail class.Use"Epam Email" for the entry title.
  addEpamEmail("some", "one").getValue() will result tosome_one@epam.com
• addPhoneNumber(int code, String number)
  Adds a contact info entry for the phone number.Please, implement this method using an anonymous class.Use"Tel" for the entry title.
  addPhoneNumber(44, "444 444-44-44").getValue() will result to+44 444 444-44-44
• addTwitter(String twitterId)
  Adds a contact info entry for the Twitter social media id.Use"Twitter" for the entry title, the given id for the value.
• addInstagram(String instagramId)
  Adds a contact info entry for the Instagram social media id.Use"Instagram" for the entry title, the given id for the value.
• addSocialMedia(String title, String id)
  Adds a contact info entry for the generic social media id.Use the given title for the entry title, the given id for the value.

Note that it is possible to rename contact with therename method.Make sure it is not possible to rename contact to havenull or empty value as the name.

One more method that theContact class have is thegetInfo() method.This method returns an array containing theContactInfo entries in the following order:

• name contact info
• phone number contact info (if set)
• email entries in order of addition (if any added)
• social media entries in order of addition (if any added)Resulting array must not contain any null values.

Important restriction: Note that in this exercise youmay not useCollections andStreams.

The purpose of this exercise is to train using nested classes.

Estimated workload of this exercise is60 min.

In this exercise we are going to design a DSL of arithmetic expressions.

AnExpression is an interface.It describes two methods:

• int evaluate() - returns the result of evaluating of the expression.
• String toExpressionString() - returns string representation of the expression.

The only non-anonymous implementation of theExpression istheVariable class.Please, implement its methods:

• public Variable(String name, int value) - a constructor of theVariable class.Sets name and value of the variable.
• public void setValue(int value) - a method to change the value of the variable.
• public int evaluate() - returns the value of the variable.
• public String toExpressionString() - returns the name of the variable.

All other implementations of theExpression interface must be anonymous, defined in static methods oftheExpressions class:

• Variable var(String name, int value) - returns aVariable with given name and value. A simple convenience method.
• Expression val(int value) - returns anExpression holding a value.Consider following methods' implementation details:
  • int evaluate() - returns the given value.
  • String toExpressionString() - returns a string representation of the given value.Enclose with(,) braces if the value is negative.
• Expression sum(Expression... members) - returns anExpression holding a sum of the given members.Consider that it is guaranteed that at least two members will be given each method call.Consider following methods' implementation details:
  • int evaluate() - returns the sum of evaluation result of all the given members.
  • String toExpressionString() - returns a string representation of the given sum.Example:sum(val(1), val(2), val(3)).toExpressionString() results to(1 + 2 + 3).
• Expression product(Expression... members) - returns anExpression holding a product of the given members.Consider that it is guaranteed that at least two members will be given each method call.Consider following methods' implementation details:
  • int evaluate() - returns the product of evaluation result of all the given members.
  • String toExpressionString() - returns a string representation of the given product.Example:product(val(1), val(2), val(3)).toExpressionString() results to(1 * 2 * 3).
• Expression difference(Expression minuend, Expression subtrahend) - returns anExpression holding a differencebetween the given minuend and the given subtrahend.Consider following methods' implementation details:
  • int evaluate() - returns the difference betweenthe given minuend evaluation result andthe given subtrahend evaluation result.
  • String toExpressionString() - returns a string representation of the given difference.Example:product(val(1), val(2)).toExpressionString() results to(1 - 3).
• Expression fraction(Expression dividend, Expression divisor) - returns anExpression holding a ratioof the given dividend to the given divisor.Note that it refers to aninteger division operation, i.e.fraction(val(3), val(4)).evaluate() result to0.Consider following methods' implementation details:
  • int evaluate() - returns the ratio of the given dividend evaluation result to the given divisor evaluation result.
  • String toExpressionString() - returns a string representation of the given fraction.Example:fraction(val(1), val(2)).toExpressionString() results to(1 / 2).

Important restriction: Note that in this exercise youmay not add more non-anonymous classes.

The purpose of this exercise is to train you to work with strings.

Estimated workload of this exercise is60 min.

Please, implementStringUtil class methods:

Method signature:

publicstaticintcountEqualIgnoreCaseAndSpaces(String[]words,Stringsample)

Return the number of words fromwords array that are equal tosample ignoring characters case and leading and trailing spaces.
Ifsample isnull orwords isnull or empty, return0.words is guaranteed to not containnull values.

Method signature:

publicstaticString[]splitWords(Stringtext)

Splittext string into array of words using following separating characters:",", ".", ";", ":", " ", "?", "!".
For empty string,null string, and string consisting only of separating characters returnnull

Method signature:

publicstaticStringconvertPath(Stringpath,booleantoWin)

Convertpath to Unix\Windows path depending on a boolean parameter.

Unix path may start with~ or/. Every subdirectory must end with/ character except the last one.Path elements. and.. refer to current directory and parent directory.Filename doesn't necessarily have the extension.
Unix path examples:

• /folder/../folder/file.txt
• /dev/null
• file.txt
• folder/logs/
• ~/user/some_logs

Windows path may start withC:. Every subdirectory must end with\ character except the last one.Path elements. and.. refer to current directory and parent directory.Filename doesn't necessarily have the extension.
Windows path examples:

• file.txt
• \Program Files\some_file.exe
• .\to_do_list.txt
• C:\Users\..\Cygwin
• .\file

Let's consider Unix~ path to correspond to WindowsC:\User path and vice versa.
Let's consider Unix/ root folder (i.e., when the path starts with/) to correspond to WindowsC:\ drive and viceversa (butC:\User still corresponds to~).

Ifpath already corresponds to the required format (for instance, is Windows path when Windows paths is needed andtoWin boolean parameter istrue) returnpath.
Ifpath isnull, empty, or doesn't correspond to any path format (Unix, Windows), returnnull.
It is guaranteed thatpath is either a correct path, or it has some of the following errors:

• More than one~
• ~ is not at the start
• ~ mixed with\ (~ in Windows path)
• More than oneC:
• C: is not at the start
• C: mixed with/ (C: in Unix path)
• \ mixed with/

Illegal paths example:

• /folder1/folder2\folder3
• C:\User/root
• /dev/~/
• C:/a/b/c/d
• ~\folder
• ~/~
• ~~
• C:\Folder\Subfolder\C:\

Method signature:

publicstaticStringjoinWords(String[]words)

Join words fromwords array and return as a string in the following format:"[str_1, str_2, ..., str_n]".

Ifwords isnull or empty returnnull.words is guaranteed to not containnull values.words may contain empty strings, ignore them, i. e. don't put them in the resulting string. Ifwords contains only empty strings returnnull.

• While implementing the methods you might need to come up withregular expressions. You may consider usingregex101.com to easier design of regular expressions.
• You can and should use following methods\classes (click on the name):
  • String.strip
  • String.split
  • String.replaceAll
  • String.replaceFirst
  • String.toLowerCase
  • String.equalsIgnoreCase
  • String.startsWith
  • String.matches
  • String.join
  • StringBuilder
  • StringJoiner
  • StringTokenizer

You may usemain method ofStringUtilclass to test your implementation.

String[]words =newString[] {"   nice ","nICE","nic3"};Stringsample ="NICE";intresult =StringUtil.countEqualIgnoreCaseAndSpaces(words,sample);// 2words =newString[]{" zoOm "," z oom"," Z O O M "};sample ="ZOOM";result =StringUtil.countEqualIgnoreCaseAndSpaces(words,sample);// 1

Stringtext =" go with ...the:;        FLOW ";String[]result =StringUtil.splitWords(text);// ["go", "with", "the", "FLOW"]text =":..,,,::: ;;;      ";result =StringUtil.splitWords(text);// null

StringwinPath ="C:\\Program Files\\my_prog_file.py";StringunixPath =StringUtil.convertPath(winPath,false);// "/Program Files/my_prog_file.py"unixPath ="../script.sh";winPath =StringUtil.convertPath(unixPath,true);// "..\\script.sh"unixPath =StringUtil.convertPath(unixPath,false);// "../script.sh"unixPath ="//home/user/somefile";winPath =StringUtil.convertPath(unixPath,true);// "C:\\home\\user\\somefile"

String[]words =newString[]{"go","with","the","","FLOW"};Stringresult =StringUtil.joinWords(words);// "[go, with, the, FLOW]"

The purpose of this exercise is to train you to work with string values.

Estimated workload of this exercise is45 min.

Please, implementvalidateColorCode method inColorCodeValidation:

This method checks the input string for compliance with the rules for writingHTML Color Codes.

While implementing the methods you might need to come up withregular expressions.You may consider usingregex101.com to ease designing them.

Note that input String may be null.

You can and should use following methods\classes:

• matches
• Pattern
• Matcher

• Examples of valid hex codes:

  #0B79E1 #6a8daf #002950

• Examples of invalid hex codes:

  123456#afafah #-123

The purpose of this exercise is to train you to work with string values.

Estimated workload of this exercise is45 min.

Please, implementvalidateEpamEmail methodinEpamEmailValidation:

This method checks the input string for compliance with the rules for a regular EPAM email. Let us define them:

• A regular EPAM email includes firstname and lastname (in English), separated by underscore ("_").
• EPAM email always ends with "@epam.com"
• When a person gets new EPAM email, but email with this firstname and lastname is already registered, we add "1" to thenew email. If such email is registered as well, we use "2" and so on.

While implementing the method you might need to come up withregular expressions. You may considerusingregex101.com to ease designing them.

Note that input value may be null.

You can and should use following methods\classes:

• matches
• Pattern
• Matcher

• Valid examples

  william_shakespeare@epam.comlu_e@epam.comwilliam_shakespeare1@epam.com william_shakespeare2@epam.com

• Invalid examples

   william@epam.com william.shakespeare@epam.com william...shakespeare@epam.com william-shakespeare@epam.com shakespeare123@epam.com william_$hakespeare@epam.com

The purpose of this exercise is to train you to work with exceptions, to raise them in particular.

Estimated workload of this exercise is30 min.

Please, implementRequirements methods:

1. requireNonNull(Object) should throw new NullPointerException if object isnull
2. requireNonNull(Object, String) should throw new NullPointerException with message if object isnull
3. checkArgument(boolean) if boolean isfalse should throw new IllegalArgumentException
4. checkArgument(boolean, String) if boolean isfalse should throw new IllegalArgumentException with message
5. checkState(boolean) if boolean isfalse should throw new IllegalStateException
6. checkState(boolean, String) if boolean isfalse should throw new IllegalStateException with message
7. checkIndex(int, int) if index out of bounds throw new IndexOutOfBoundsException. Index must be inside[0, size) section.

Such methods might be helpful to check arguments, object states.

The purpose of this exercise is to train you to work with exceptions, to handle them in particular.

Estimated workload of this exercise is30 min.

Please, implement the main method inCatchEmAll class.It must handle a call to a risky method that can throw different types of exceptions.

Please, note that some types of exceptions should be handled, while others – shouldn’t.

Details:

The purpose of this exercise is to train you to work with generics.

Estimated workload of this exercise is30 min.

Please, use generics to changeHouse class in order to dogs cannot enter cats' house and cats cannot enter dogs' house.

You need to alterresidents field andenter methods of theHouse class.

Note that if you have done everything right, then two particular lines in theMain class may prevent successful compilation, so you may need to remove them.See details in theMain class.

The purpose of this exercise is to train you to work with enums.

Estimated workload of this exercise is60 min.

Please, implement methods inDirection class:

• ofDegrees - Return a Direction instance by input degrees ornull if there is none.
• closestToDegrees - Return the closest Direction instance to input degrees.
• opposite - Return a Direction instance that is opposite to this.
• differenceDegreesTo - Return the difference in degrees between this and input Direction instance.

Note that degrees input value may be out of the [0; 360) range. Adjust them accordingly.

The purpose of this exercise is to train you to work with wrapper classes and their static methods.

Estimated workload of this exercise is3 hours.

Please, implement methods inBattleship8x8 class.

Battleship8x8 represents a 8x8 map forBattleship game.An important detail is that Battleship8x8 uses aships field of long type to store ships locationsand ashots field of long type to register shots.

Fields of long type value store 64 bits each. Consider them as 8 rows per 8 cells.'0' bits represent empty cells, '1' bits represent cells seized by ships or registered shots.

• public boolean shoot(String shot) - Registers a shot and returnstrue if the shot hits a ship.A shot is a combination of one of A-H letters and one of 1-8 digits
• public String state() - Returns a string representing state of the map.Map string is 8 lines per 8 characters separated by "\n". Use following symbols:
  • '.' - an empty cell
  • '×' - an empty cell that has been shot
  • '☐' - a cell seized by a ship
  • '☒'- a cell seized by a ship that has been shot

You must not add or change new fields.Consider using static methods of wrapper classes.

Consider a map information encoded as a long value:

longmap = -1150950973573693440L;

You may consider it represented as binary literal:

/*    11110000    00000111    00000000    00110000    00000010    01000000    00000000    00000000 */longmap = 0b11110000_00000111_00000000_00110000_00000010_01000000_00000000_00000000L;

Consider rows be marked with digits and columns be marked with letters:

/*    ABCDEFGH   ┌────────  1│11110000  2│00000111  3│00000000  4│00110000  5│00000010  6│01000000  7│00000000  8│00000000 */

Consider the following list of shots:

List<>shots =List.of("A1","B2","C3","D4");

Then we could useBattleship8x8 API:

Battleship8x8battle =newBattleship8x8(map);shots.forEach(battle::shoot);System.out.println(battle.state());

The result would be the following:

☒☐☐☐.....×...☐☐☐..×.......☐☒..........☐..☐......................

The purpose of this exercise is to train you to work with arrays and optional.

Estimated workload of this exercise is45 min.

Implementmax method ofMaxMethod class.

The correct implementation should receive an array ofint values and return its maximum value.

Details:

• the method returns the result as OptionalInt
• if the input array is empty ornull, return empty OptionalInt.

int[]vals =newint[]{-2,0,10,5};OptionalIntresult =MaxMethod.max(vals);System.out.println(result.getAsInt() ==10);// true

The purpose of this exercise is to prepare you to work with collections—to create and add elements and iterate through them to perform operations on each element.

Duration:45 minutes

In this task, you will simulate the work of a new post office that takes parcels weighing between 0.5 and 20 kg and with a maximum volume of 0.25 m3

TheBox class describes parcels. A parcel has the following characteristics: sender, recipient, weight, volume, and shipping cost. All characteristics except for the shipping cost are passed to the constructor to create an object. The shipping cost is calculated based on the weight, volume, and value of the parcel.

TheNewPostOffice class has:

• NewPostOffice()
  Creates an office (an empty collection of parcels)
• Collection<Box> getListBox()
  Returns a collection of parcels in the office
• static BigDecimal calculateCostOfBox(double weight, double volume, int value)
  Calculates the cost of a parcel

Please proceed to the NewPostOffice class and implement its methods using an iterator:

• Collection<Box> deliveryBoxToRecipient(String recipient)
  Returns all parcels of a specified recipient; any parcels found must be removed from the office
• void declineCostOfBox(double percent)
  Changes the cost of each parcel in the office by the percentage specified
• boolean addBox(String sender, String recipient, double weight, double volume, int value)
  Creates a parcel, calculates its shipping cost, and adds it to the office

• The sender and receiver must exist.
• The weight must be 0.5–20.0 kg.
• The volume must be greater than 0 and less than 0.25 m3.
• The value must be greater than zero.
• The cost of a parcel is calculated as follows: the weight is multiplied by the cost of one kilogram, the volume is multiplied by the cost of one cubic meter, the value is multiplied by a given coefficient, then everything is summed up.
• If the values of the data above are set incorrectly (by specifying invalid values), the java.lang.IllegalArgumentException is thrown.

You may not use the Lambdas or the Streams API.

The purpose of this exercise is to describe, create, and use lists that are built according to special rules.

Duration:45 minutes

In this task, you will describe a list that is based on a dynamic array. The internal structure of the list is a one-dimensional array of theObject type with an initial capacity/size of 10 and a size field that stores the number of elements in the list. You must provide for the expansion of the array (list) capacity when the number of elements reaches 75% (load factor 0.75) of its size. Use the following expression to calculate the increase in capacity: Doub le the current capacity of the array and then multiply it by the load factor.

Now, please proceed to theSimpleArrayListImpl class, which implements theSimpleArrayList interface, and provide implementations of the following methods:

• int size()
  Returns the number of elements

• String toString()
  Makes a string representation of the list

• boolean add(Object element)
  Appends the specified element to the end of the list

• Object get(int index)
  Returns an element at a specified position in the list

• Optional<Object> remove(Object element)
  Searches for and removes the specified element

• int capacity()
  Returns the current length of the list

• boolean decreaseCapacity()
  Decreases the capacity of the list if it is 40% full or less

• The list is created by the default constructor, which creates an internal array with an initial length of 10 elements.
• The list cannot containnull elements. The add and remove methods must throw aNullPointerException if they get null.
• The get method must throwIndexOutOfBoundsException if the index is outside the [0 … size - 1] range.
• The size field specifies the number of elements in the list and where to place the next element.
• The method for adding a new element must first check whether the capacity of the list should be increased before adding it.
• ThedecreaseCapacity() method calculates the new capacity by doubling the current number of elements.
• You can add any private methods to theSimpleArrayListImp class.

You may not:

• Use any type from thejava.util package (or its subpackages) except for:
  • java.util.Iterator
  • java.util.Optional
• Add any additional fields into theSingleArrayListImpl class.
• Add any additional public methods to theSingleArrayListImpl class.

The purpose of this exercise is to create and use a custom doubly linked list.

Duration:1 hour

In this task, you will describe a bidirectional list based on a linked representation. The internal structure of the list is a node chain (nested classNode) where each node encapsulates a list element and has one reference to the previous node and one reference to the following node. The first node has no reference to the previous node, and the last node has no reference to the next one.

Now, please proceed to theDoublyLinkedListImpl class, which implements theDoublyLinkedList interface, and provide implementations of the following methods:

• boolean addFirst(Object element)
  Inserts an element at the beginning of the list and returns true if an element is successfully added and, if not, false

• boolean addLast(Object element)
  Appends an element to the end of this list and returns true if an element is successfully added and, if not, false

• boolean delete(int index)
  Deletes an element by index and throwsIndexOutOfBoundsException if the index is out of range

• Optional<Object> remove(Object element)
  Returns and deletes the first occurrence of the specified element in the list

• boolean set(int index, Object element)
  Finds the element at the specified index and replaces it or throws theIndexOutOfBoundsException if the index is out of range

• int size()
  Returns the number of elements in the list

• Object[] toArray()
  Returns an array containing all the elements in order from first to last

• String toString()
  Returns a string representation of the list

• TheDoublyLinkedListImpl class has two fields, head and tail, and should not contain a size field to store the number of elements.
• The list is created by the default constructor, which initializes the head and tail fields to null.
• The list cannot contain null elements. The add, remove, and set methods must throw aNullPointerException if they get null.
• The remove method must use the equals method to find the occurrence of the object in the list.
• The string representation of a list consists of all its elements separated by a space. For example, if a list contains three elements, o1, o2, and o3, thetoString method returns "s1 s2 s3", wheres1=o1.toString(),s2=o2.toStribng(), ands3=o3.toString().

You may not:

• Use any type from thejava.util package or its subpackages except forjava.util.Optional
• Add additional fields to theDoublyLinkedListImpl andDoublyLinkedListImpl.Node classes
• Add any additional methods to theDoublyLinkedListImpl.Node class except constructors

The purpose of this exercise is to work with List implementations, add/delete elements, and iterate over a collection to perform operations on each element.

Duration:1 hour

In this task, you will simulate the work of the New Post Storage service, which accepts parcels (boxes) and prepares them for distribution to New Post offices.TheBox class describes a parcel with the following characteristics:sender,recipient,weight,volume,cost,city, andoffice. All characteristics are passed to the constructor to create an object. You must not change this class.

TheNewPostOfficeStorage interface has several methods that performadd,delete,filter, andupdate operations in a storage:

• boolean acceptBox(Box box)
  Appends the specified parcel to the end of this storage
• boolean acceptAllBoxes(Collection<Box> boxes)
  Appends to this storage all parcels that are contained inthe specified collection. It must add either all the parcelsor nothing, if an exception occurs
• boolean carryOutBoxes(Collection<Box> boxes)
  Removes from this storage all of its parcels that are containedin the specified collection
• List<Box> carryOutBoxes(Predicate<Box> predicate)
  Removes from this storage all of its parcels that are satisfied thespecified predicate
• List<Box> getAllWeightLessThan(double weight)
  Selects all parcels whose weight is less than the parameter value.
• List<Box> getAllCostGreaterThan(BigDecimal cost)
  Selects all parcels whose cost is greater than the parameter value.
• List<Box> getAllVolumeGreaterOrEqual(double volume)
  Selects all parcels whose volume is greater than or equalto the parameter value
• List<Box> searchBoxes(Predicate<Box> predicate)
  Searches parcels using a predicate. This method doesnot change the original storage
• void updateOfficeNumber(Predicate<Box> predicate, int newOfficeNumber)
  Updates theoffice field in each box of this storage

Please, proceed to theNewPostOfficeStorageImplthat the implementor ofNewPostOfficeStorage interface.

Its highly recommended avoid indexed access to elements of a collection.

TheMain class is not under tests. You can use it for your own purposes.

• Because theBox class does not have any identity field theimplementationmust not check uniqueness ofBox instances.
• Because theNewPostOfficeStorage describes business logicnot a collection, an implementationmust not extend anyexisting implementation ofList interface or implement itinternallybut must aggregate it instead.
• You should choose the best existing implementation of thejava.util.List interface from the Java collection framework.
• The implementationmust not permit null values and must throwNullPointerException in such cases.
• It is forbidden to use:
  • lambda when you implement functional interfaces.
  • stream(),contains(),containsAll()indexOf() methodsofList interface.
  • for ( i ) loop (use aforeach loop orIterator with awhile() loop or theforeach() method instead).

The purpose of this exercise is for you to practice using collections, namely Set.

Duration:45 minutes

In this task, you need to demonstrate how to work with a set of integers encapsulated in theRangedOpsIntegerSet class.

Please proceed to the RangedOpsIntegerSet class and provide implementations of the following methods:

• boolean add(final Integer integer)
  Adds a single value to the set

• boolean remove(final Object o)
  Removes a single value from the set

• boolean add(int fromInclusive, int toExclusive)
  Adds a range of values to the set (first argument—inclusive; last argument—exclusive); returns true if range values were actually added

• boolean remove(int fromInclusive, int toExclusive)
  Removes a range of values from the list (first argument—inclusive; last argument—exclusive); returns true if range values were actually removed

• Iterator<Integer> iterator()
  Returns an iterator to iterate over elements of the set in natural order

• int size()
  Returns the number of current elements

You may not use lambdas or streams when implementing this task.

1. Adding one range:

RangedOpsIntegerSetset =newRangedOpsIntegerSet();set.add(1,5);for(Integerel :set){System.out.println(el);}

Output:

1234

2. Adding two ranges:

RangedOpsIntegerSetset =newRangedOpsIntegerSet();set.add(1,5);set.add(9,11);for(Integerel :set){System.out.println(el);}

1234910

3. Adding and removing ranges:

RangedOpsIntegerSetset =newRangedOpsIntegerSet();set.add(1,15);set.remove(3,12);for(Integerel :set){System.out.println(el);}

12121314

The purpose of this exercise is to give you some practice using collections of the Set type.

Duration:1 hour

In this task, you will determine the percentage of compliance of a certain team with project requirements. In other words, you will determine if the team is suitable for the project.

You have the following description:

• ThePosition enum defines a set of positions.
• TheSkill enum defines a set of skills.
• TheLevel enum defines a set of skill levels.
• TheMember class defines a team member. Each member has a name, a level, and a set of skills (a collection of theSet<Skill> type implemented asEnumSet<Skill>). TThe team is described as a set of members in the form ofHashSet<Member>.
• TheRole class defines the role of the participant in the project. Each role has a level, a position, and required skills (a collection of theSet<Skill> type implemented as anEnumSet<Skill>).
• TheProject class defines the project and contains a description of it and a list of roles.
• TheProject.Entry class combines a skill and its level and is used in the algorithm for calculating the team's compliance with the project.

Now, please proceed to theMember class and implement its contents:

• public Member(String name, Level level, Skill... skills)
  Creates a member with the specified name, level, and skills
• Getters
  Return values of the appropriate fields

Now, please proceed to theRole class and implement its contents:

• public Role(Position position, Level level, Skill... skills)
  Creates a role with the specified position, level, and skills
• Getters
  Return values of the appropriate fields

Now, please proceed to theProject class and implement its contents:

• public Project(Role... roles)
  Creates a project with the specified roles
• public List<Role> getRoles()
  Returns a list of roles
• public int getConformity(Set<Member> team)
  Returns the percentage of team compliance with the project requirements
• private static class Entry {}
  Describes an entry containing a level/skill pair

• TheEntry must implement the equals andhashCode methods. Two entries are considered equal if and only if they have the same skill and level.
• •To calculate the percentage of team compliance with project requirements, you must use the following algorithm:
  • Generate a list of pairs<Level, Skill> for the project's roles (e.g., named projectEntries).
  • Save the size of this list to a variable (e.g., originalSize).
  • Generate a list of pairs<Level, Skill> for the team members (e.g., named teamEntries).
  • Remove common elements from both lists.
  • Calculate the compliance percentage as follows:
    • Subtract the current size of the list of entries for the project roles from the originalSize variable
    • Multiply the difference by 100
    • Divide by the original size of the list of entries for the project roles

You may not:
•Add extra fields to classes
•Add extra methods to classes
•Use lambdas or streams when implementing this task

1. Suppose the project has the following roles:

•DEVELOPER which has the A1 level and the JAVA, DATABASE skills •KEY_DEVELOPER which has the A3 level and the JAVA, DATABASE, SPRING skills •TESTER which has the A2 level and the JAVA, SPRING, TESTING_TOOLS skills

Then the list of pairs will be:

projectEntries → [<A1, JAVA>, <A1, DATABASE>, <A3, JAVA>, <A3, DATABASE>, <A3, SPRING>, <A2, JAVA>, <A2, SPRING>, <A2, TESTING_TOOLS>]

And the list size is 8.

2. Suppose the team has the following members:

•Member1 which has the A1 level and the JAVA, SPRING skills •Member2 which has the A2 and the JAVA, DATABASE, SPRING skills

Then the list of pairs will be:

teamEntries → [<A1, JAVA>, <A1, SPRING>, <A2, JAVA>, <A2, DATABASE>, <A2, SPRING>]

3. Removing the common elements in both lists yields the following result:

projectEntries → [<A1, DATABASE>, <A3, JAVA>, <A3, DATABASE>, <A3, SPRING>, <A2, TESTING_TOOLS>]teamEntries → [<A1, SPRING>, <A2, DATABASE>]

The new size of the projectEntries list is 5.

4. The compliance percentage is 37.5%.

The purpose of this exercise is to learn how to useMap collections.

Duration:1 hour 30 minutes

In this task, you will simulate work with a book catalog. The catalog can be represented as theTreeMap collection, where the author is the key and the list of published books is the value. You have the following description:

• TheAuthor class, which consists of the first and last name
• TheBook class, which consists of the title, genre, and cost

Since the book catalog is an ordered map, theAuthor andBook classes must implement theComparable interface.TheBooksCatalog class must have two constructors: a default one and one with a parameter that creates a map based on an existing map.

Please proceed to theAuthor andBook classes and provide implementations of thecompareTo() method.

Please, proceed to theBooksCatalog class and provide implementations of the following methods:

• List<Book> findByAuthor(Author author)
  Returns a list of books by the specified author ornull if there is no such author in the catalog
• List<Author> findAuthorsByBook(Book book)
  Returns a list of the authors of the specified book ornull if there is no such book in the catalog
• String getAllAuthors()
  Returns a list of all the authors as a String
• Set<Book> findBooksByGenre(String pattern)
  Returns a set of books of the specified genre ornull if there are no books of this genre
• Map<Book, List<Author>> findAuthorsByBookTitle(String pattern)
  Returns the book/author pair map. The search is carried out based on the words in the book's title

• To order the map by author, apply alphabetical order by first name and, if the names match, alphabetical order by last name.
• To order the map by book title, apply alphabetical order by title and, if the titles match, by ascending cost.
• ThefindAuthorsByBookTitle method searches for books based on a word pattern; it is case-insensitive.
• ThefindBooksByGenre method searches for books of a certain genre specified as a search pattern; the matching pattern and name of the genre are case-insensitive; all the books found are sorted using natural ordering.
• You can use a regular expression to match occurrences of a pattern in a book title or genre in thefindBooksByGenre andfindAuthorsByBookTitle methods.
• ThegetAllAuthors method returns an alphabetical list of authors as a String, where the authors' names are separated by '\n'.
• No methods of theBooksCatalog class acceptnull, and they must throw aNullPointerException if they do.
• You can use thegetData() method in the Util class to create the initial map.
• You can add any private methods to theBooksCatalog class.

You may not use lambdas or streams when implementing this task.

The purpose of this exercise is to work with Comparator implementations on the TreeMap maps.

Duration:1 hour

In this task, you will simulate the work of the student's gradebook. The internal structure of the gradebook is a collection of theTreeMap type where a key is an object of theStudent type, the value is aHashMap whose key is the name of a discipline (an object of theString type), and the value is the grade (an object of theBigDecimal type).
TheStudent class describes a student with the following characteristics:first/last name andgroup. All characteristics are passed to the constructor to create an object.You must not change this class.
Now, please proceed to theStudentsGradebookImpl class, which implements theStudentsGradebook interface, and provide implementations of the following methods:

• public GradeBookImpl()
  Creates the gradebook object in which aComparator is described to compare students
• boolean addEntryOfStudent(Student student, String discipline, BigDecimal grade)
  Adds a student entry to the gradebook; returns true if the addition was successful, and false if not.
• int size()
  Returns the number of students in the gradebook
• Comparator<Student> getComparator()
  Returns theComparator, which is used to compare students
• List<String> getStudentsByDiscipline(String discipline)
  Gets a list of strings with students' names and their grades for the specified disciplines in the format"first_last name : grade"
• Map<Student, Map<String, BigDecimal>> removeStudentsByGrade(BigDecimal grade)
  Finds, removes, and returns from the gradebook students who have a grade below the specified one in any discipline
  If no such students are found, an empty map will be returned
• Map<BigDecimal, List<Student>> getAndSortAllStudents()
  Gets the gradebook as an ordered map where the key is the average grade and the value is a list of theStudent type

• Since theStudent objects are the keys to the gradebook, when you create the gradebook, you will need to declare theComparator to compare objects of theStudent type and pass it to theTreeMap<Student, Map<String, BigDecimal>> constructor.
• The grading scale for any discipline is in the range[0 .. 5]. The minimum passing grade is3 points.
• TheremoveStudentsByGrade method returns a map ordered by theStudent type. To create the resulting map, you must use theComparator applied in the gradebook constructor.
• ThegetAndSortAllStudents method generates a gradebook based on the student's average grade. The average grade is indicated in increments of one tenth—for example, 3.1, 3.2, 3.3, etc.
• It is guaranteed that the parameters passed to all methods are correct.
• You can add any private methods to theStudentsGradebookImpl class.

You may not use lambdas or streams to complete this task.

The purpose of this exercise is to apply various algorithms to collections using the methods of theCollections class.

Duration:1 hour

In this task, you will simulate the work of a weekly maternity hospital journal. The internal structure of the journal is a collection of theMap type, where the key is the weekday (an enum of theWeekDay type) and the value is a list of babies born during the week (objects of theBaby type).
TheBaby class describes a baby with the following characteristics:name,weight,height,gender, andbirth time. All characteristics are passed to the constructor to create an object.You must not change this class.
Please note that once a birth journal has been created and filled in, it cannot be changed. This needs to be guaranteed.
Now, please proceed to theBirthJournalManagementImpl class, which implements theBirthJournalManagement interface, and provide implementations of the following methods:

• boolean addEntryOfBaby(WeekDay day, Baby baby)
  Adds an entry for the specified baby to the journal; returns true if the addition was successful and false if not
• void commit()
  Makes the journal immutable
• int amountBabies()
  Returns the number of babies born in a given week
• List<Baby> findBabyWithHighestWeight(String gender)
  Finds the baby of the specified gender with the highest weight
  If there are multiple babies, it sorts them alphabetically by name.
• List<Baby> findBabyWithSmallestHeight(String gender)
  Finds the baby of the specified gender with the smallest height
  If there are multiple babies, it sorts them in order of increasing weight
• Set<Baby> findBabiesByBirthTime(String from, String to)
  Finds babies born in the specified time period

• Time of birth is given as aString in the form"hour:minute".
• For implementations of all methods, the parameters passed to them are guaranteed to be correct.
• You can add any private methods to theBirthJournalManagementImpl class.

You may not use lambdas or streams to complete this task.

The purpose of this task is to practice with reading, processing and writing to a file using Java *Reader/*Writerclasses and their buffered variants, and usingtry-with-resources.

Duration:1.5 hours

In this task you will implementLicenseReader#collectLicenses(File, File) method. It must read all license filesfromroot, format these licenses to a specific format and write all of them intooutputFile.root might be a directory or just a regular file. Please note that you need to collect files not only from theroot directory, but also from its subdirectories and their subdirectories, etc. All non-license files must be ignored.Be aware, that this method must not throw any checked exception.

Take a look at the license header format:

---License: <license name>Issued by: <issuer>Issued on: <date>Expires on: <date>---

The order of these properties is not restricted, so you may expect thatExpires on might occur earlier thanLicense. All of them are mandatory except forExpires on. The date format is ISO date (yyyy-mm-dd). The licenseis wrapped between lines containing 3 dashes (---). The file always starts with license header, otherwise it's justa regular file.

If license header is invalid, thenIllegalArgumentException must be thrown. If eitherroot oroutputFile is null,thenIllegalArgumentException must be thrown. Ifroot does not exist, or it's not readable, then the sameexception must be thrown. And ifroot is a directory, but is not executable (means that it could not be entered),thenIllegalArgumentException must be thrown.

The output format for just one license looks like:

License for <file name> is <license name> issued by <issuer> [<issuedOn date> - <expiresOn date>]

Each line must contain the information about license in this format. If license does not have an expiration date,then instead of<expiresOn date> -unlimited must be used.

IfoutputFile exists, then it must be cleared. So no appending is allowed.

• collectLicenses method must verify thatroot is:
  • not null
  • exists
  • readable
  • if it's a directory, then that it's executable
• collectLicenses method must verify thatoutputFile is not null
• ifoutputFile is not empty, then it must be cleared before writing to it
• all files and directories ofroot must be processed
• non-license files must be ignored
• license files must be processed and info about it must be stored inoutputFile (see formats inDescriptionsection)
• if license format is invalid, or any verification is failed, thenIllegalArgumentException must be thrown
• all license properties are mandatory, except forExpires on (it's optional)
• the order of license properties are undefined
• the order in the resulting file does not matter
• ifExpires on is omitted, then inunlimited must be used
• collectLicenses does not throw any checked exception
• BufferedWriter/BufferedReader must be used for IO operations
• All IO buffered streams must be defined usingtry-with-resources syntax

libA/libraryA.lic

---License: GNUIssued by: GNU CommitetIssued on: 2020-01-01Expires on: 2025-01-01---Library description...

libraryB.lic

---License: CustomIssued by: GovermentIssued on: 1984-04-13---Top secret info...

output

License for libA/libraryA.lic is GNU issued by GNU Commitet [2020-01-01 - 2025-01-01]License for libraryB.lic is Custom issued by Goverment [1984-04-13 - unlimited]

The purpose of this exercise is to give you some practice managing I/O streams.

It should take you about30 minutes to complete this task.

You will implement an input stream to process data from the file. Please also implement a util class to check a file andreturn a ciphered text.

Please implement methods in theCipherCreator class.

• public static StringBuilder cipherText(File input) - takes a file as an input and returns a ciphered text.

Please override methods in theTransformerInputStream class.

• public int read() - reads the next data byte and returns a ciphered byte.
• public void close() - closes the stream and prints a message about it to the console.

Cipher key points:

1. The text can only contain letters, and each word is written on a new line.
2. Each letter of the ciphered text is shifted by two characters from the original one, case-sensitive. A -> C, f ->h.
3. The alphabet is looped. It means Z -> B, y -> a.
4. All other characters are ignored.

TestcipherForFundamentalsOfProgrammingXYZzyxCamelCaseDiScOcipherText(file);//      Vguv//      ekrjgt//      Hqt//      Hwpfcogpvcnu//      Qh//      Rtqitcookpi//      ZAB//      baz//      EcognEcug//      FkUeQ

"Hi"10101        !--!cipherText(file);// Jk////

The purpose of this exercise is to practice the usage of JavaScanner andFormatter classes.

Estimated workload of this exercise is60 minutes.

The Car class represents a car with some attributes:

• brand
• model
• cylinder capacity
• performance
• acceleration

The first part of the exercise is to read cars from a CSV (comma-separated values) file.The CSV file contains the car attributes in the same order as listed above.

Implement theCarCsvReader class'sreadCars(File file) method to do the job.

• Read the file content line-by-line withBufferedReader. Then create aScanner and configure it to use comma (,) as delimiter.

Input file example:

Toyota,Corolla,1599,75,6.8Kia,Rio,1225,68,10.3

Once the cars are in memory, print them to the console in the following way

• brand: 10 characters width
• model: 10 characters width
• cylinder capacity: 5 digits, add measurement unit: ccm
• performance: 3 digits, add measurement unit: kw
• acceleration: 5 digits, add measurement unit: sec

Implement theFormattedCarPrinter class'sprint(List<Car> cars) method.

Output example, given the above list of cars:

    Toyota    Corolla  1599 ccm  75 kw  6.80 sec       Kia        Rio  1250 ccm  68 kw 10.30 sec

TheApplication class is already implemented, which delegatesthe reading task toCarCsvReader class, and the formatting task toFormattedCarPrinter class.

The starter project includes a samplecars.csv file indata directory. The application has to read that file.

The purpose of this exercise is to train you to manage files and directories using Java NIO.

Duration:1.5 hour

You must implement a method to build a directory representation. You can also create other methods for convenience that will be called from the 'tree' method.

Please implement methods in theFileTree class.

• public Optional<String> tree(final Path path) - takes a path to a file/directory as an input parameter and builds a String representation of its hierarchy.

1. If a given pathdoes not exist, return an empty Optional.

2. If a given pathrefers to a file, return a String with its name and size like this:

   some-file.txt 128 bytes

3. If a given pathrefers to a directory, return a String with its name, total size and full hierarchy:

`

some-dir 100 bytes├─ some-inner-dir 50 bytes│  ├─ some-file.txt 20 bytes    │  └─ some-other-file.txt 30 bytes└─ some-one-more-file.txt 50 bytes

`

• Use pseudo-graphic characters to format the output.
• Compute the size of a directory as a sum of all its contents.
• Sort the contents in the following way:
  • Directories should go first.
  • Directories and files are sorted in lexicographic order (case-insensitive).

The purpose of this exercise is to familiarize you with the mechanism of complex object serialization/deserialization.

Duration:1 hour

In this exercise, you need to implement the serialization of complex objects of theOrder type. Below is a hierarchy of classes that describe orders.

TheOrder class represents an order:

• id
  A unique identifier of the order
• total
  The cost of the order, which is automatically calculated and can only be read
• items
  A map that stores products (a ke y is an object of theItem type) and the number of units to be purchased (a value is a variable of theint type)

TheItem class represents a product:

• id
  A unique identifier of the product
• name
  The name of the product
• description
  A short description of the product
• characteristics
  A list of product features (objects of theItemCharacteristic type)

The abstract classItemCharacteristic represents one characteristic of a product and is the supertype for different types of product characteristics:

• id
  A unique identifier of the characteristic
• name
  The name of the characteristic
• type
  A data type of the characteristic (It can beString,Integer,Double, etc.)

TheIntItemCharacteristic class represents an integer characteristic and inherits theItemCharacteristic class:

• value
  Keeps a value of the characteristic

TheDoubleItemCharacteristic class represents a numeric characteristic and inherits theItemCharacteristic class:

• value
  Keeps a value of the characteristic

TheOrderSerializer class serializes and deserializes objects of theOrder class:

• public static void serializeOrder(Order order, OutputStream out) throws IOException
  Serializes a specified object of the Order class into the given data output stream
• public static Order deserializeOrder(InputStream in) throws IOException, ClassNotFoundException
  Deserializes a specified object of theOrder class from the given data input stream

• •Each entity class must contain a constructor that accepts values for all fields and can contain any other constructors if necessary.

• •All entity classes must have getters and setters for all fields.

• •All entity classes must contain an overriddenequals() method by all fields.

• •TheItemCharacteristic class must beabstract and must not implement theSerializable interface.

• •When calculating the cost of an order in theOrder class, set thetotal field value using the following algorithm:

  1. If thetotal field isnull and theitems field is notnull, then a call of thegetTotal() method must calculate thetotal value.
  2. If theitems field isnull, thetotal must be zero.
  3. It is guaranteed that the internal state of theitems field will not change after being installed in the object.

• •The custom serialization mechanism must be implemented in all descendants of theItemCharacteristic class because it is not serializable.

• You may not use the serialization mechanism with theExternalizable interface.

The purpose of this task is to train you to declare your functional interface,practice a little more with generics, and see an example of why you might want todeclare your interface when we have plenty of predefined ones.

Duration:15 minutes

In this task, you'll implement the so-calledThrowingFunction.It's a variant of ajava.util.function.Function, except for it may throwan exception. It might be really helpful when you want to pass a functionto some method, but the underlying code throws some checked exception(it happens pretty often, when you work with Java IO, for example).

But what exception it might throw?IOException, orClassNotFoundException,or justException, or evenThrowable? Well, let's try to use generics here.We want to declare a function that would throw an exception, which we can specify.

There is also a pretty common practice to define "companion" methods for suchfunctions. Usually, they called something likesilent,wrap,quiet, etc.The main idea of such companions is to wrap the throwing function and returnthe non-throwing function. It's useful when you need to pass your throwing functionto some API that accepts only non-throwing ones (e.g. Stream API).

Let's go through the requirements of this task:

• ThrowingFunction interface must be declared underedu.epam.fop.lambdas package
• It must be a generic type with generalized:
  • Argument type
  • Return type
  • Exception type
• It must have an abstractapply method, which accepts one argument,of one generic type and returns an instance of another generic type
• apply method must be able to throw any exception up toThrowable
• It must have a static method for wrappingThrowingFunction intoFunction,namedquiet
• quiet method must be generic too
• quiet method must returnnull whennull is passed
• quiet method must not throw any exception
• The returned byquiet methodFunction must wrap any occurredinThrowingFunction exception intoRuntimeException without hiding the cause
• The returned byquiet methodFunction must workjust asThrowingFunction, when no error has occurred
• generic types ofThrowingFunction andFunction must correspond to each other
• Generic types must not have any boundaries if possible
• ThrowingFunction must be annotated with@FunctionalInterface

ThrowingFunction<String,Integer,IOException>ioFunc =newThrowingFunction<>() {@OverrideIntegerapply(StringfileName)throwsIOException {returnIOUtils.getSize(fileName);  }}

try {returnioFunc.apply("big-file.csv");}catch (IOExceptione) {e.printStackTrace();}

Function<String,Integer>func =ThrowingFunction.quiet(ioFunc);func.apply("big-file.csv");

The purpose of this task is to practice writing simple and concise Java lambda expressions.

Duration:30 minutes

Your task is to provide a Java lambda expression that implementsDoubleFunction<String>.

As the name of the functional interface indicates it accepts adouble value,which we want to format to the correspondingString value in the format:

[-]\d+[.\d] %

Where[...] means optional,\d means digit, and+ means at least one symbol.Please note, the space between the number and percent sign. This lambda must never returnnull.

The passed value can be anything, even more than1 or less than0.The value1 we consider100 %, so-0.5 would be-50 %.

• Convert thedouble value to the correspondingString value, representing the double value as a percent string.
• Never returnnull.
• A- sign before the number in a string of negative values.
• A space between the resulting number and the percent sign.
• A maximum of one digit in the fraction part.
• You must round the fraction part mathematically, i.e. anything less than0.5 is rounded down (floor),and anything greater than or equal to0.5 is rounded up (ceil). For example:
  • 1.4 =>1
  • 2.45 =>2
  • 3.5 =>4
  • 17.7000001 =>18
• (Optional) Make the lambdaone line (i.e., without using curly brackets)

The lambda can be tested using the following call, which returns aString value for testing:

PercentageFormatter.INSTANCE.apply(<doublevalue>);

And here are some expected input/output pairs:

• 0.42 =>42 %
• 0.427 =>42.7 %
• 0.4273 =>42.7 %
• 0.4275 =>42.8 %
• -0.4275 =>-42.8 %

The purpose of this task is to practice with Optional, and its main methods -map,filter,flatMap, etc.

Duration:3 hours

In this task, you are provided with some classes that are used for insurance calculations.In theinsurance package you have:

1. Subject - the main sealed interface, which must be implemented by insurance subjects.
2. Car,Accommodation,Person - the subject's insurance is calculated for (which implement theSubject interface).
3. Currency - just anenum of the currencies provided.
4. RepeatablePayment - represent, for example, rent, salary, or a loan.
5. Injury,Family - not subject classes; used to describe a certain part of the subject classes.

These classes a mostly plain data objects without any logic. The only things to highlight are:

1. Some getters returnOptional instead of the target type.
2. Some of these classes implementComparable interface to make it easier to retrieve the required instancefromSortedSet.

Also, you havecalculator package. Here you have two main classes:

1. InsuranceCoefficient - a wrapper forint value in range[0; 100],which represents the percentage of trustworthy clients.
2. InsuranceCalculator<S extends Subject> - a functional interface,which determinesInsuranceCoefficient based on the passedS instance.

Also, here you can find several*InsurancePolicies classes, which provide methods that must be implemented.Take a closer look at them and define the requirements.

No implementations must throw an exception, and all of them must benull-safe. Objects can benull or returnnull.Getters that returnOptional never returnnull.

All arguments cannot benull.

AcceptsBigInteger divider which is used to adjust the insurance coefficient.

It must return an insurance coefficient when an accommodation is rented; monthly payment should be inUSD.As a result, for the insurance coefficient, you must divide the rent amount by the divider provided.If the resulting insurance coefficient is more than100, thenInsuranceCoefficient.MAX is returned.If a condition is not met, then return emptyOptional.

1. The accommodation must includerent.
2. The rent period must be in months.
3. The rent currency must beUSD.
4. The rent amount must be greater than0.
5. The coefficient is equal to rent divided by the divider provided in percent (rent / divider * 100%).
6. If the relation is more than100%,100% should be returned.
7. The default value isOptional.empty

AcceptsBigInteger priceThreshold, which must be met or exceeded by the accommodation price,int roomsThreshold, which must be met or exceeded by the room counts,andareaThreshold are the same but for the accommodation area.

Accommodations price, room count, and the area must be greater or equal to their corresponding thresholds.If all the conditions are met,InsuranceCoefficient.MAX must be returned;if notInsuranceCoefficient.MIN must be returned.

1. Accommodation price >=priceThreshold
2. Accommodation rooms >=roomsThreshold
3. Accommodation area >=areaThreshold
4. ReturnInsuranceCoefficient.MAX if all conditions are met
5. ReturnInsuranceCoefficient.MIN if one or more conditions are not met

AcceptsLocalDate baseDate, which is used as a pivot point for calculations. All calculations must use it.Date-math precision is1 day.

The calculator must return:

1. InsuranceCoefficient.MAX if the manufactured date is less than1 year frombaseDate
2. A coefficient of70 if less than5 years
3. A coefficient of30 if less than10 years
4. InsuranceCoefficient.MIN if a car is older than10 years.
5. If the manufactured date is unknown,Optional.empty must be returned

AcceptsLocalDate baseDate as a base for the date-math calculations,BigInteger priceThreshold which must be met or exceeded by car price,andPeriod owningThreshold - the minimum period of ownership.

The idea is to calculate the insurance coefficient only for cars which are still owned by a person (soldDate is not set),price is greater or equal topriceThreshold, the period frompurchaseDate tobaseDateis greater or equal toowningThreshold.

The resulting coefficient must be based on car price andpriceThreshold.If the price of the car is greater than or equal to three times thepriceThreshold,InsuranceCoefficient.MAX must be returned. If it exceeds two times but is less than three times greater,a coefficient of50 must be returned.InsuranceCoefficient.MIN must be returnedif the price is less than or equal to twice the threshold.If any of the conditions are not met,Optional.empty must be returned.

1. soldDate must not be set.
2. price must be >= thanpriceThreshold.
3. purchaseDate +owningThreshold must be >=baseDate.
4. InsuranceCoefficient.MAX must be returned ifprice >=3 *priceThreshold.
5. A coefficient of50 must be returned if3 *priceThreshold >price >=2 *priceThreshold.
6. InsuranceCoefficient.MIN must be returned ifprice <2 *priceThreshold.
7. Optional.empty must be returned if any of the conditions are not met.

Acceptsint childrenCountThreshold. The coefficient must be calculated based on the number of childrena person has relative to the threshold provided.

1. A person must have afamily.
2. A person must havechildren.
3. The resulting coefficient equals tomax(100, childrenCount / threshold).
4. InsuranceCoefficient.MIN must return if any of the conditions are not met.

AcceptsBigInteger salaryThreshold andSet<Currency> currencies,which together define the salary threshold based on the amount and the currency allowed.

1. Person must have an employment history of at least four records.
2. They must have multi-currency account.
3. They must not have any recorded injuries.
4. They must have at least one accommodation (either owned or rented).
5. They must be currently employed (i.e., the last employment record does not haveendDate).
6. salary for this job must be in one of thecurrencies provided.
7. salary.amount must be greater than or equal tosalaryThreshold.
8. If all conditions are met, a coefficient of 50 must be returned.
9. If any of the conditions are not met,Optional.empty must be returned.

AcceptsSet<EmergencyStatus> statuses, which defines the allowed emergency statusesof an accommodation owned or rented by a person.

1. A person must have an accommodation.
2. The calculator must pick the accommodation that is the smallest in area.
3. Check to make sure itsemergencyStatus is listed in thestatuses parameter.
4. The coefficient is calculated as100 * (1 - status.ordinal() / totalStatuses).
5. If any of the conditions are not met,Optional.empty must be returned.

AcceptsBigInteger rentThreshold.

1. A person must have an injury.
2. The injury must have been caused by someone else.
3. The largest accommodation (by area) must be rented.
4. The rent must be inGBP.
5. The coefficient is calculated asmax(100, 100 * rent / threshold).
6. If any of the conditions are not met,Optional.empty must be returned.

The purpose of this exercise is to train you in usage of Java Stream API in basic level.

Estimated workload of this exercise is30 minutes.

MovieQueries class is responsible to perform different queries on a list of movie titles.Please implementMovieQueries constructor and methods according to the following method definitions.Please do not change method names, arguments, or return type of the methods:

MovieQueries constructor must throwIllegalArgumentException if the parameter is null.

In this exercise use Stream API, do not implementfor loop,while loop or any other imperative approach.

Having the following test data:

"Terminator", "Blade Runner", "Star Wars", "Indiana Jones", "Friends","The Magnificent Seven", "The Dark Knight", "The Lord of the Rings: The Return of the King","Pulp Fiction"

• getNumberOfMoviesThatStartsWith called with parameter"The", returns 3.
• getFirstTitleThatContainsThreeWords returns"The Magnificent Seven"

TheApplication class is already implemented, which delegatesthe querying task toMovieQueries class.

The purpose of this exercise is to practice Java Stream API at intermediate level.The data model is similar to the previous exercise, movie. In this exercise the model is based on movies, but more complex.

Estimated workload of this exercise is90 minutes.

The stream operations are defined on movie data. There are two domain model classes:Movie andPerson.Person can be the director, writer or cast of the movie..

Person example:

name: Arnold Schwarzeneggerdate of birth: July 30, 1947biography: With an almost unpronounceable surname and a thick Austrian accent

Movie example:

title: The Terminatordescription: A human soldier is sent from 2029 to 1984 to stop an almost indestructible cyborg killing machine.genres: ACTION, SCI_FIlength: 107 (minutes)release year: 1984directors: James Cameronwriters: James Cameron, Gale Anne Hurd, William Wishercasts: Arnold Schwarzenegger, Linda Hamilton, Michael Biehn

Note: directors, writers and casts fields are collections that hold Person reference.

MovieQueries class is responsible to perform different queries on a list of movies.Please implementMovieQueries constructor and methods according to the following method definitions.Please do not change method names, arguments, or return type of the methods:

MovieQueries constructor must throwIllegalArgumentException if the passed parameter is null.

InMovieQueries implementation you can expect that theMovie and relatedPerson objects passed as arguments are all valid,each field is populated with non-null values. No need to validate them.

Use only Java Stream API.

Having the following movies:

The Terminatorgenres: ACTION, SCI_FIBlade Runnergenres: ACTION, SCI_FI, DRAMAIndiana Jonesgenres: ACTION, ADVENTURE

• checkGenreOfAllMovies(Genre.SCI_FI) returns false
• checkGenreOfAnyMovies(Genre.SCI_FI) returns true

TheApplication class is already implemented, which delegates the querying task toMovieQuery class.You can find the models inmodel package.MovieDataStore builds test data and provide them to the application.Classes inbuilder package helps to create models.