LeetCode 48. Rotate Image
Problem:
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 NOT allocate 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] ]
Example 2:
Given input matrix =
[ [ 5, 1, 9,11],
[ 2, 4, 8,10],
[13, 3, 6, 7],
[15,14,12,16] ],
rotate the input matrix in-place such that it becomes:
[ [15,13, 2, 5],
[14, 3, 4, 1],
[12, 6, 8, 9],
[16, 7,10,11] ]
-Summary-
1. Reverse the matrix first
2. Transpose the matrix to move around the elements. The element will be rotated with 90 degrees. (Clockwise)
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