Given a 2D binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area.
Example:
Input:
1 0 1 0 0
1 0 1 1 1
1 1 1 1 1
1 0 0 1 0
Output: 4
用dp来记录以i,j为右下角元素时最大的matrix。状态转移方程比较trick
Solution:
class Solution(object): def maximalSquare(self, matrix): """ :type matrix: List[List[str]] :rtype: int """ res = 0 dp = [[0 for i in range(len(matrix[0]))] for j in range(len(matrix))] for i in range(len(matrix)): for j in range(len(matrix[0])): dp[i][j] = 1 if matrix[i][j]=='1' else 0 if i>0 and j>0 and matrix[i][j]=='1': dp[i][j] = 1 + min(dp[i-1][j-1],min(dp[i-1][j],dp[i][j-1])) res = max(res,dp[i][j]) return res*res
来源:https://www.cnblogs.com/bernieloveslife/p/11178266.html