[LeetCode] Rotate Image

[LeetCode] Rotate Image
 

Rotate Image

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

Rotate the image by 90 degrees (clockwise ).

Follow up:
Cocould you do this in-place?

Solution:

The question requires an in-situ algorithm. Assume that the coordinate axis is shown in the preceding figure. Rotating 90 degrees clockwise is equivalent to first turning the image along x = n/2, and then turning the image along y = x diagonal lines. The Code is as follows:

 

Class Solution {public: void rotate (vector

 
  
> & Matrix) {int len = matrix. size (); // first flip the left and right sides of the matrix for (int I = 0; I

  
   
& V) {int len = v. size (); int I = 0, j = len-1; while (I

   
    
& V, int I, int j) {int temp = v [I]; v [I] = v [j]; v [j] = temp ;}};