Spiral Matrix
问题描述
Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
For example,
Given the following matrix:
[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]
You should return [1,2,3,6,9,8,7,4,5]
.
程序
public class Solution { public List<Integer> spiralOrder(int[][] matrix) { List<Integer> path = new ArrayList<Integer>(); if (matrix == null || matrix.length == 0 || matrix[0].length == 0) { return path; } int i = 0, j = 0; int n = matrix.length, m = matrix[0].length; int cnt = n * m; int cyc = 0; while (true) { // to right while (j < m - cyc) { path.add(matrix[i][j++]); } --j; ++i; // to bottom while (i < n - cyc) { path.add(matrix[i++][j]); } --i; --j; if (path.size() == cnt) { break; } // to left while (j >= cyc) { path.add(matrix[i][j--]); } ++j; --i; // to top while (i > cyc) { path.add(matrix[i--][j]); } ++i; ++j; if (path.size() == cnt) { break; } ++cyc; } return path; } }