[LeetCode] Rotate Image

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?

需要O(N)的辅助空间，应该有个O(1)空间的。但似乎比较复杂。

class Solution {
public:
    void rotate(vector<vector<int> > &matrix) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<int> temp(matrix.size());
        
        int begX = 0;
        int begY = 0;
        int endX = matrix.size() - 1;
        int endY = matrix[0].size() - 1;
        
        while(begX < endX)
        {
            for(int i = begY + 1; i <= endY - 1; i++)
                temp[i] = matrix[begX][i];
                
            int index = endX - 1;
            for(int i = begY + 1; i <= endY - 1; i++)
                matrix[begX][i] = matrix[index--][begY];
                
            index = begY + 1;
            for(int i = begX + 1; i <= endX - 1; i++)
                matrix[i][begY] = matrix[endX][index++];
             
            index = endX - 1;   
            for(int i = begY + 1; i <= endY - 1; i++)
                matrix[endX][i] = matrix[index--][endY];
                
            for(int i = begX + 1; i <= endX - 1; i++)
                matrix[i][endY] = temp[i];
                
            int t = matrix[begX][begY];
            
            matrix[begX][begY] = matrix[endX][begY];
            matrix[endX][begY] = matrix[endX][endY];
            matrix[endX][endY] = matrix[begX][endY];
            matrix[begX][endY] = t;
            
            begX++;
            begY++;
            endX--;
            endY--;
        }
    }
};