[LeetCode] Rotate Image

最新推荐文章于 2021-08-31 14:50:55 发布

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#Algorithms #LeetCode #Matrix

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本文介绍了一个二维矩阵旋转算法，该算法能够将一个 n x n 的二维矩阵按顺时针方向旋转90度，并且实现了原地操作，无需额外的空间。

Total Accepted: 7942 Total Submissions: 26120

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

Rotate the image by 90 degrees (clockwise).

Follow up:
Could you do this in-place?

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