[프로그래머스] 가장 큰 정사각형 찾기 - Python

def solution(board):
    answer = 0
    for i in range(1,len(board)):
        for j in range(1,len(board[i])):
            if board[i-1][j-1]>=1 and board[i-1][j]>=1 and board[i][j-1]>=1 and board[i][j]>=1:
                board[i][j]= min(board[i-1][j-1],board[i-1][j],board[i][j-1])+1
    arr=list()
    for i in range(len(board)):
        arr.append(max(board[i]))
    answer = max(arr)
    return answer**2