原地置换
1:对角线交换
2:每行以中心交换
import java.util.*; public class Solution { public int[][] rotateMatrix(int[][] mat, int n) { // write code here for(int i = 0;i < n;i++){ for(int j = i + 1;j < n;j++){ int t = mat[i][j]; mat[i][j] = mat[j][i]; mat[j][i] = t; } } for(int i = 0;i < n;i++){ for(int j = 0;j < n / 2;j++){ int t = mat[i][j]; mat[i][j] = mat[i][n - 1- j]; mat[i][n - 1 - j] = t; } } return mat; } }