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| 1 | +<h2><a href="https://leetcode.com/problems/rotate-image">48. Rotate Image</a></h2><h3>Medium</h3><hr><p>You are given an <code>n x n</code> 2D <code>matrix</code> representing an image, rotate the image by <strong>90</strong> degrees (clockwise).</p> |
| 2 | + |
| 3 | +<p>You have to rotate the image <a href="https://en.wikipedia.org/wiki/In-place_algorithm" target="_blank"><strong>in-place</strong></a>, which means you have to modify the input 2D matrix directly. <strong>DO NOT</strong> allocate another 2D matrix and do the rotation.</p> |
| 4 | + |
| 5 | +<p> </p> |
| 6 | +<p><strong class="example">Example 1:</strong></p> |
| 7 | +<img alt="" src="https://assets.leetcode.com/uploads/2020/08/28/mat1.jpg" style="width: 500px; height: 188px;" /> |
| 8 | +<pre> |
| 9 | +<strong>Input:</strong> matrix = [[1,2,3],[4,5,6],[7,8,9]] |
| 10 | +<strong>Output:</strong> [[7,4,1],[8,5,2],[9,6,3]] |
| 11 | +</pre> |
| 12 | + |
| 13 | +<p><strong class="example">Example 2:</strong></p> |
| 14 | +<img alt="" src="https://assets.leetcode.com/uploads/2020/08/28/mat2.jpg" style="width: 500px; height: 201px;" /> |
| 15 | +<pre> |
| 16 | +<strong>Input:</strong> matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]] |
| 17 | +<strong>Output:</strong> [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]] |
| 18 | +</pre> |
| 19 | + |
| 20 | +<p> </p> |
| 21 | +<p><strong>Constraints:</strong></p> |
| 22 | + |
| 23 | +<ul> |
| 24 | + <li><code>n == matrix.length == matrix[i].length</code></li> |
| 25 | + <li><code>1 <= n <= 20</code></li> |
| 26 | + <li><code>-1000 <= matrix[i][j] <= 1000</code></li> |
| 27 | +</ul> |
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