rotate-image.cpp

//https://leetcode.com/problems/rotate-image/

class Solution {
public:
    void rotate(vector<vector<int>>& matrix) {
        int n=matrix.size();
        int left = 0, right = n-1;
        int top = 0, bottom = n-1;
        while(left<right && top < bottom){
            for(int i=0; i<(right-left);i++){
                //use reverse order
                //save top left
                int temp = matrix[top][left+i];
                
                //move bottom left to top left
                matrix[top][left+i] = matrix[bottom-i][left];
                //move bottom right to bottom left
                matrix[bottom-i][left] = matrix[bottom][right-i];
                //move top right to bottom right
                matrix[bottom][right-i] = matrix[top+i][right];
                //move top left to top right
                matrix[top+i][right] = temp;                         
            }
            
            left++;
            right--;
            top++;
            bottom--;
        }
    }
};