221. Maximal Square
Medium
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.lengthn == matrix[i].length1 <= m, n <= 300matrix[i][j]is'0'or'1'.