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Commite2a6b02

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Merge pull requestTheAlgorithms#753 from abhijay94/Development
Added the algorithm and test for Fibonacci Search
2 parents0276ccd +09c4cd7 commite2a6b02

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packagesrc.main.java.com.search;
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importstaticjava.lang.Math.min;
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/**
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* Fibonacci search is a method of searching a sorted array using a divide and conquer algorithm that narrows down
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* possible locations with the aid of Fibonacci numbers. Compared to binary search where the sorted array is divided
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* into two equal-sized parts, one of which is examined further, Fibonacci search divides the array into two parts that
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* have sizes that are consecutive Fibonacci numbers.
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* <p>
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* Worst-case performanceO(Log n)
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* Best-case performanceO(1)
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* Average performanceO(Log n)
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* Average space complexityO(1)
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*/
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publicclassFibonacciSearch {
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/**
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* @param array is an array where the element should be found
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* @param key is an element which should be found
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* @param <T> is any comparable type
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* @return The index position of the key in the array, returns -1 for empty array
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*/
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public <TextendsComparable<T>>intfindIndex(T[]array,Tkey) {
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intsize =array.length;
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if (size ==0)
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return -1;
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// Initialize the fibonacci numbers
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intfibN1 =1;// (n-1)th Fibonacci term
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intfibN2 =0;// (n-2)th Fibonacci term
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intfibN =fibN1 +fibN2;// nth Fibonacci term
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// fibN should store the smallest Fibonacci Number greater than or equal to size
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while (fibN <size) {
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fibN2 =fibN1;
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fibN1 =fibN;
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fibN =fibN2 +fibN1;
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}
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// Marks the eliminated range from front
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intoffset = -1;
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while (fibN >1) {
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// Check if fibN2 is a valid location
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inti =min(offset +fibN2,size -1);
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// If key is greater than the value at index fibN2, cuts the sub-array from offset to i
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if (array[i].compareTo(key) <0) {
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fibN =fibN1;
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fibN1 =fibN2;
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fibN2 =fibN -fibN1;
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offset =i;
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}
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// If x is greater than the value at index fibN2, cuts the sub-array after i+1
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elseif (array[i].compareTo(key) >0) {
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fibN =fibN2;
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fibN1 =fibN1 -fibN2;
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fibN2 =fibN -fibN1;
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}elsereturni;// Element found
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}
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// comparing the last element with key
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if (fibN1 ==1 &&array[offset +1].compareTo(key) ==0)
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returnoffset +1;
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return -1;// Element not found
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}
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}
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packagesrc.test.java.com.search;
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importorg.junit.Assert;
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importorg.junit.Test;
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importsrc.main.java.com.search.FibonacciSearch;
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publicclassFibonacciSearchTest {
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@Test
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publicvoidtestFibonacciSearch() {
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FibonacciSearchfibonacciSearch =newFibonacciSearch();
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Integer[]arr = {11,14,23,32,36,40,54,69};
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intx =54;
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intindex =fibonacciSearch.findIndex(arr,x);
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Assert.assertEquals("Incorrect index",6,index);
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Integer[]arrTwo = {-400, -283, -180, -160, -129, -120, -30};
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x = -120;
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index =fibonacciSearch.findIndex(arrTwo,x);
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Assert.assertEquals("Incorrect index",5,index);
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String[]arrString = {"101","122","136","165","225","351","458"};
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StringstringX ="136";
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index =fibonacciSearch.findIndex(arrString,stringX);
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Assert.assertEquals("Incorrect index",2,index);
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String[]arrThree = {};
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Assert.assertEquals("Incorrect index", -1,fibonacciSearch.findIndex(arrThree,""));
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}
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}

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