rotate-image

gistfile1.cpp

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

/*
tese case

1 2 3 4 
5 6 7 8 
9 10 11 12
13 14 15 16

13 9 5 1
14 10 6 2
15 11 7 3
16 12 8 4

in-place

단순한 규칙을 찾고 loop를 2D로 구현하여야 함.
*/


class Solution {
public:
    void rotate(vector<vector<int> > &matrix) {
        int size = matrix.size();
        int halfSize = size/2; 
        
        for(int i=0; i<halfSize ; ++i) {
            for(int j=i ; j<size-1-i ; ++j) {
                int temp = matrix[i][j];
                
                matrix[i][j] = matrix [size-1-j][i];
                matrix[size-1-j][i] = matrix[size-1-i][size-1-j];
                matrix[size-1-i][size-1-j] = matrix[j][size-1-i];
                matrix[j][size-1-i] = temp;
            }
        }
        
    }
};