【Leetcode Summary】旋轉圖像

You are given an n x n 2D matrix representing an image.

Rotate the image by 90 degrees (clockwise).

Note:

You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOTallocate another 2D matrix and do the rotation.

Example 1:

Given input matrix = 
[
  [1,2,3],
  [4,5,6],
  [7,8,9]
],

rotate the input matrix in-place such that it becomes:
[
  [7,4,1],
  [8,5,2],
  [9,6,3]
]      

solution:就是直接按照矩陣對角線翻轉一次，然後再按照X軸中線上下翻轉一次，代碼如下：

void rotate(int** matrix, int matrixRowSize, int matrixColSize) {
    int i,j;
    int tmp;
 
    for (i=0;i<matrixRowSize-1;i++) {
    	for (j=0;j<matrixColSize-i;j++) {
            tmp=matrix[i][j];
        matrix[i][j]=matrix[matrixColSize - 1- j][matrixRowSize - 1 - i];
        matrix[matrixColSize - 1- j][matrixRowSize - 1 - i]= tmp;   
 
    	}
    }
    
     for (i=0;i<matrixRowSize/2;i++) {
    	for (j=0;j<matrixColSize;j++) {
            tmp=matrix[i][j];
        matrix[i][j]=matrix[matrixRowSize - 1 - i][j];
        matrix[matrixRowSize - 1 - i][j]= tmp;   
 
    	}
    }
}