```
class Solution {
public void rotate(int[][] matrix) {
int n = matrix.length-1;
for(int i=0; i<n+1/2; i++){
for(int j=i; j<n-i; j++){
int temp = matrix[i][j];
matrix[i][j] = matrix[n-j][i];
matrix[n-j][i] = matrix[n-i][n-j];
matrix[n-i][n-j] = matrix[j][n-i];
matrix[j][n-i] = temp;
}
}
}
}
```