倒置一下,然后左右镜像一下
class Solution {
public:
void rotate(vector<vector<int>>& matrix) {
int L = matrix.size();
for (int i = 0; i < L; ++i)
for (int j = i + 1; j < L; ++j)
swap(matrix[i][j], matrix[j][i]);
for (int i = 0; i * 2 + 1 < L; ++i)
for (int j = 0; j < L; ++j)
swap(matrix[j][i], matrix[j][L - 1 - i]);
}
};