題目：

題解：

class Solution:def maximalSquare(self, matrix: List[List[str]]) -> int:if len(matrix) == 0 or len(matrix[0]) == 0:return 0maxSide = 0rows, columns = len(matrix), len(matrix[0])dp = [[0] * columns for _ in range(rows)]for i in range(rows):for j in range(columns):if matrix[i][j] == '1':if i == 0 or j == 0:dp[i][j] = 1else:dp[i][j] = min(dp[i - 1][j], dp[i][j - 1], dp[i - 1][j - 1]) + 1maxSide = max(maxSide, dp[i][j])maxSquare = maxSide * maxSidereturn maxSquare