Leetcode 1895. Largest Magic Square

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

2. Solution

**解析：**根据幻方定义，分别检查主对角线、副对角线、各行、各列的和是否相等，按阶次从大到小依次检查，碰到满足条件的返回阶。

• Version 1

class Solution:def largestMagicSquare(self, grid: List[List[int]]) -> int:m = len(grid)n = len(grid[0])size = min(m, n)for k in range(size, 0, -1):for i in range(m-k+1):for j in range(n-k+1):if self.check(grid, i, j, k):return kdef check(self, grid, x, y, k):main_diagonal = 0secondary_diagonal = 0for i in range(k):main_diagonal += grid[x+i][y+i]secondary_diagonal += grid[x+i][y+k-i-1]if main_diagonal != secondary_diagonal:return Falsefor i in range(k):row = sum(grid[x+i][y:y+k])if row != main_diagonal:return Falsecolumn = sum([grid[x+j][y+i] for j in range(k)])if column != main_diagonal:return Falsereturn True

Reference

1. https://leetcode.com/problems/largest-magic-square/