leetcode 48. Rotate Image
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 =
[
,
,
],
rotate the input matrix in-place such that it becomes:
[
,
,
]
Example 2:
Given input matrix =
[
[ 5, 1, 9,11],
[ 2, 4, 8,10],
,
],
rotate the input matrix in-place such that it becomes:
[
,
,
,
]
class Solution {
public void rotate(int[][] matrix) {
if(matrix.length == 0) return;
int row = matrix.length -1;
int col = matrix.length -1;
int repeat = 0;
for(int i = 0 ; i <= row/2; i++){
for(int j = 0 ; j <= col /2 ; j++){
if(row % 2 == 0 && i == row/2 && j != col/2) continue;
swap(matrix, i ,j);
}
}
}
public void swap(int[][] matrix, int i, int j){
int row = matrix.length - 1;
int col = matrix.length - 1;
int temp = matrix;
matrix = matrix;
matrix = matrix;
matrix = matrix;
matrix = temp;
}
}
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