def largest_square(ba: list[list[int]]) -> int: n=len(ba) m=len(ba[0]) dp=[[n * 0 for i in range(m)]] max_num = -1 for i in range(n): for j in range(m): if ba[i][j]==0: continue left = right = diag = 0 if i>0: left = dp[i-1][j] if j>0: right = dp[i][j-1] if (i>0 and j>0): diag = dp[i-1][j-1] dp[i][j] = min([left,right,diag])+1 max_num = max(max_num, dp[i][j]) return max_num ab = [[0,1,0,1],[1,1,1,0],[0,1,1,0],[0,0,0,1]] print(largest_square(ab))