# 0048 - Rotate Image

[0048 - Rotate Image](https://leetcode.com/problems/rotate-image/)

GYou are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).

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.

## Examples

![](https://assets.leetcode.com/uploads/2020/08/28/mat1.jpg)

Input: matrix = \[\[1,2,3],\[4,5,6],\[7,8,9]] Output: \[\[7,4,1],\[8,5,2],\[9,6,3]]

![](https://assets.leetcode.com/uploads/2020/08/28/mat2.jpg)

Input: matrix = \[\[5,1,9,11],\[2,4,8,10],\[13,3,6,7],\[15,14,12,16]] Output: \[\[15,13,2,5],\[14,3,4,1],\[12,6,8,9],\[16,7,10,11]]

Input: matrix = \[\[1]] Output: \[\[1]]

Input: matrix = \[\[1,2],\[3,4]] Output: \[\[3,1],\[4,2]]

## Constraints

* matrix.length == n
* matrix\[i].length == n
* 1 <= n <= 20
* -1000 <= matrix\[i]\[j] <= 1000

## Java Solution

```java
class Solution {
    public void rotate(int[][] matrix) {
        for(int i = 0; i < (matrix.length + 1) / 2; i++) {
            for(int j = 0; j < matrix.length / 2; j++) {
                int temp = matrix[matrix.length - 1 - j][i];
                matrix[matrix.length - 1 - j][i] = matrix[matrix.length - 1 - i][matrix.length - 1 - j];
                matrix[matrix.length - 1 - i][matrix.length - 1 - j] = matrix[j][matrix.length - 1 - i];
                matrix[j][matrix.length - 1 - i] = matrix[i][j];
                matrix[i][j] = temp;
            }
        }
    }
}
```
