[LeetCode]Rotate Image

[cpp]
class Solution { 
//the key is to find the independent circle in the matrix  
public: 
    void rotate(vector<vector<int> > &matrix) { 
        // Start typing your C/C++ solution below  
        // DO NOT write int main() function  
        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; 
            } 
        } 
    } 
};