Leetcode 1914. Cyclically Rotating a Grid

快来打我* 2022-09-05 14:51 8阅读 0赞

文章作者：Tyan  
博客：[noahsnail.com][] | [CSDN][] | [简书][Link 1]

## 1. Description ##

![Cyclically Rotating a Grid][]

## 2. Solution ##

\*\*解析：\*\*Version 1，先根据规律求出每一层的索引，然后按逆时针顺序保存到数组中，则`k`次循环后当前索引的位置`index`在列表中的位置为`(index+k) % len(circle)`，因此将当前索引位置的值赋给目标索引位置即可。

*  Version 1

class Solution:
        def rotateGrid(self, grid: List[List[int]], k: int) -> List[List[int]]:
            m = len(grid)
            n = len(grid[0])
            result = [[0] * n for _ in range(m)]
            for i in range(min(m // 2, n // 2)):
                circle = []
                # Left column
                circle += [(j, i) for j in range(i, m-i)]
                # Bottom row
                circle += [(m-1-i, j) for j in range(i+1, n-i)]
                # Right column
                circle += [(j, n-1-i) for j in range(m-2-i, i-1, -1)]
                # Top row
                circle += [(i, j) for j in range(n-2-i, i, -1)]
                for index, (x, y) in enumerate(circle):
                    target_x, target_y = circle[(index+k) % len(circle)]
                    result[target_x][target_y] = grid[x][y]
            return result

## Reference ##

1.  [https://leetcode.com/problems/cyclically-rotating-a-grid/][https_leetcode.com_problems_cyclically-rotating-a-grid]

[noahsnail.com]: http://noahsnail.com
[CSDN]: http://blog.csdn.net/quincuntial
[Link 1]: http://www.jianshu.com/users/7731e83f3a4e/latest_articles
[Cyclically Rotating a Grid]: /images/20220829/36c4378058e8401487194171327a5296.png
[https_leetcode.com_problems_cyclically-rotating-a-grid]: https://leetcode.com/problems/cyclically-rotating-a-grid/