标签：style blog color io for ar div log amp
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
Could you do this in-place?
思路：对于matrix[i][j]，其顺时针旋转：1) 90度对应的点为matrix[j][n-1-i]; 2) 180度对应的点为matrix[n-1-i][n-1-j]; 3) 270度对应的点为matrix[n-1-j][i]。注意边界条件。
1 class Solution { 2 public: 3 void rotate( vector<vector<int>> &matrix ) { 4 int n = matrix.size(); 5 for( int i = 0; i < n/2; ++i ) { 6 for( int j = i; j < n-i-1; ++j ) { 7 int tmp = matrix[i][j]; 8 matrix[i][j] = matrix[n-1-j][i]; 9 matrix[n-1-j][i] = matrix[n-1-i][n-1-j]; 10 matrix[n-1-i][n-1-j] = matrix[j][n-1-i]; 11 matrix[j][n-1-i] = tmp; 12 } 13 } 14 return; 15 } 16 };
标签：style blog color io for ar div log amp
原文地址：http://www.cnblogs.com/moderate-fish/p/3939359.html
