Given a matrix of M x N elements (M rows, N columns), return all elements of the matrix in diagonal order as shown in the below image.
Example:
Input: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] Output: [1,2,4,7,5,3,6,8,9] Explanation:
Note:
The total number of elements of the given matrix will not exceed 10,000.
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My solution:
public class Solution { public int[] findDiagonalOrder(int[][] matrix) { if (matrix == null || matrix.length == 0) return new int[0]; int m = matrix.length; int n = matrix[0].length; int[] re = new int[m * n]; boolean flag = true; int mnow = 0; int nnow = 0; for (int i = 0; i < m * n; ++i) { re[i] = matrix[mnow][nnow]; if (flag) { if (mnow == 0 || nnow == n - 1) { if (nnow == n - 1) mnow++; else nnow++; flag = false; } else { mnow--; nnow++; } } else { if (mnow == m - 1 || nnow == 0) { if (mnow == m - 1) nnow++; else mnow++; flag = true; } else { mnow++; nnow--; } } } return re; } }