题目:
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?
class Solution {
public:
void rotate(vector<vector<int> > &matrix) {
int n = matrix.size();
for (int i = 0; i < n / 2; i++) {
for (int j = i; j < n - 1 - i; j++) {
int tmp = matrix[i][j];
matrix[i][j] = matrix[n - 1 - j][i];
matrix[n - 1 - j][i] = matrix[n - 1 - i][n - 1 - j];
matrix[n - 1 - i][n - 1 - j] = matrix[j][n-1-i];
matrix[j][n - 1 - i] = tmp;
}
}
}
};