You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
//给定一个n*n的矩阵，顺时针旋转90度
class Solution { public: void rotate(vector<vector<int> > &matrix) { if(matrix.size()==0) return ; int n = matrix.size(); for(int i =0;i<n;++i) for(int j=0;j<n-i;j++){ int temp = matrix[i][j]; matrix[i][j] = matrix[n-1-j][n-1-i]; matrix[n-1-j][n-1-i] = temp; } for(int i =0;i < n/2;++i) for(int j = 0;j < n;++j){ int temp = matrix[i][j]; matrix[i][j] = matrix[n-1-i][j]; matrix[n-1-i][j] = temp; } } };
原文：http://www.cnblogs.com/xiuxiu55/p/6514079.html