maximal-square

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Description

Given an m x n binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area.

 

Example 1:

Input: matrix = [["1","0","1","0","0"],["1","0","1","1","1"],["1","1","1","1","1"],["1","0","0","1","0"]]
Output: 4

Example 2:

Input: matrix = [["0","1"],["1","0"]]
Output: 1

Example 3:

Input: matrix = [["0"]]
Output: 0

 

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 300
• matrix[i][j] is '0' or '1'.

Solution(Python)

class Solution:
    def maximalSquare(self, A):
        maxSol = 0
        for i in range(len(A)):
            for j in range(len(A[i])):
                A[i][j] = int(A[i][j])
                if A[i][j] and i and j:
                    A[i][j] = min(A[i - 1][j], A[i - 1]
                                  [j - 1], A[i][j - 1]) + 1
                if maxSol < A[i][j]:
                    maxSol = A[i][j]
        return maxSol * maxSol