Nov 11, 2020 · Nov 10, 2020
diff --git a/src/main/java/com/fishercoder/solutions/_498.java b/src/main/java/com/fishercoder/solutions/_498.java
 package com.fishercoder.solutions;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;

 public class _498 {

    public static class Solutoin1 {
        }
    }

    /*
        matrix = new int[][]{
                {1, 2, 3},
                {4, 5, 6},
                {7, 8, 9},
                {10, 11, 12},
                {13, 14, 15},
        };
        expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 10, 13, 11, 9, 12, 14, 15};
    */
    public static class Solutoin2 {
        public int[] findDiagonalOrder(int[][] matrix) {
                if(matrix == null || matrix.length == 0){
                    return new int[0];
                }
                List<List<Integer>> diagonals = new ArrayList<>();
    int maxRow = matrix.length;
    int maxCol = matrix[0].length;
    int maxDiagonal = maxRow + maxCol - 1;
    for (int diagonalIndex = 0; diagonalIndex < maxDiagonal; diagonalIndex++) {
    int curRowIdx = (diagonalIndex < maxCol) ? 0 : (diagonalIndex - maxCol + 1);
    int curColIdx = (diagonalIndex < maxCol) ? diagonalIndex : (maxCol - 1);
    List<Integer> diagonal = new ArrayList<Integer>();
    while (curRowIdx >= 0 && curRowIdx < maxRow && curColIdx >= 0 && curColIdx < maxCol) {
    int diagonalElement = matrix[curRowIdx][curColIdx];
    diagonal.add(diagonalElement);
    curRowIdx++;
    curColIdx--;
    }
    diagonals.add(diagonal);
    }
    int[] result = new int[maxRow * maxCol];
    int resultIdx = 0;
    for (int i = 0; i < diagonals.size(); i++) {
    List<Integer> diagonal = diagonals.get(i);
    if (i % 2 == 0) {
    Collections.reverse(diagonal);
    }
    for (int j = 0; j < diagonal.size(); j++) {
    result[resultIdx] = diagonal.get(j);
    resultIdx++;
    }
    }
    return result;
        }
    }

 }
diff --git a/src/test/java/com/fishercoder/_498Test.java b/src/test/java/com/fishercoder/_498Test.java
 */
 public class _498Test {
    private static _498.Solutoin1 solutoin1;
    private static _498.Solutoin2 solutoin2;
    private static int[][] matrix;
    private static int[] expected;

    @BeforeClass
    public static void setup() {
        solutoin1 = new _498.Solutoin1();
        solutoin2 = new _498.Solutoin2();
    }

    @Test
        expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 10, 13, 11, 9, 12, 14, 15};
        assertArrayEquals(expected, solutoin1.findDiagonalOrder(matrix));
    }

    @Test
    public void test3() {
        matrix = new int[][]{
                {1, 2, 3},
                {4, 5, 6},
                {7, 8, 9},
        };
        expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 9};
        assertArrayEquals(expected, solutoin2.findDiagonalOrder(matrix));
    }

    @Test
    public void test4() {
        matrix = new int[][]{
        {2,5},{8,4},{0,-1}
        };
        expected = new int[]{2,5,8,0,4,-1};
        assertArrayEquals(expected, solutoin2.findDiagonalOrder(matrix));
    }
 }
Original file line number	Diff line number	Diff line change
		@@ -1,5 +1,9 @@
		package com.fishercoder.solutions;

		import java.util.ArrayList;
		import java.util.Collections;
		import java.util.List;

		public class _498 {

		public static class Solutoin1 {
Expand DownExpand Up		@@ -47,4 +51,51 @@ public int[] findDiagonalOrder(int[][] matrix) {
		}
		}

		/*
		matrix = new int[][]{
		{1, 2, 3},
		{4, 5, 6},
		{7, 8, 9},
		{10, 11, 12},
		{13, 14, 15},
		};
		expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 10, 13, 11, 9, 12, 14, 15};
		*/
		public static class Solutoin2 {
		public int[] findDiagonalOrder(int[][] matrix) {
		if(matrix == null \|\| matrix.length == 0){
		return new int[0];
		}
		List<List<Integer>> diagonals = new ArrayList<>();
		int maxRow = matrix.length;
		int maxCol = matrix[0].length;
		int maxDiagonal = maxRow + maxCol - 1;
		for (int diagonalIndex = 0; diagonalIndex < maxDiagonal; diagonalIndex++) {
		int curRowIdx = (diagonalIndex < maxCol) ? 0 : (diagonalIndex - maxCol + 1);
		int curColIdx = (diagonalIndex < maxCol) ? diagonalIndex : (maxCol - 1);
		List<Integer> diagonal = new ArrayList<Integer>();
		while (curRowIdx >= 0 && curRowIdx < maxRow && curColIdx >= 0 && curColIdx < maxCol) {
		int diagonalElement = matrix[curRowIdx][curColIdx];
		diagonal.add(diagonalElement);
		curRowIdx++;
		curColIdx--;
		}
		diagonals.add(diagonal);
		}
		int[] result = new int[maxRow * maxCol];
		int resultIdx = 0;
		for (int i = 0; i < diagonals.size(); i++) {
		List<Integer> diagonal = diagonals.get(i);
		if (i % 2 == 0) {
		Collections.reverse(diagonal);
		}
		for (int j = 0; j < diagonal.size(); j++) {
		result[resultIdx] = diagonal.get(j);
		resultIdx++;
		}
		}
		return result;
		}
		}

		}
Original file line number	Diff line number	Diff line change
Expand Up		@@ -11,12 +11,14 @@
		*/
		public class _498Test {
		private static _498.Solutoin1 solutoin1;
		private static _498.Solutoin2 solutoin2;
		private static int[][] matrix;
		private static int[] expected;

		@BeforeClass
		public static void setup() {
		solutoin1 = new _498.Solutoin1();
		solutoin2 = new _498.Solutoin2();
		}

		@Test
Expand All		@@ -42,4 +44,24 @@ public void test2() {
		expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 10, 13, 11, 9, 12, 14, 15};
		assertArrayEquals(expected, solutoin1.findDiagonalOrder(matrix));
		}

		@Test
		public void test3() {
		matrix = new int[][]{
		{1, 2, 3},
		{4, 5, 6},
		{7, 8, 9},
		};
		expected = new int[]{1, 2, 4, 7, 5, 3, 6, 8, 9};
		assertArrayEquals(expected, solutoin2.findDiagonalOrder(matrix));
		}

		@Test
		public void test4() {
		matrix = new int[][]{
		{2,5},{8,4},{0,-1}
		};
		expected = new int[]{2,5,8,0,4,-1};
		assertArrayEquals(expected, solutoin2.findDiagonalOrder(matrix));
		}
		}