1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
| """
Given a 2D binary matrix filled with 0's and 1's,
find the largest square containing only 1's and return its area.
1 0 1 0 0
1 0 1 1 1
1 1 1 1 1
1 0 0 1 0
Output: 4
"""
def maximalSquare(self, matrix: List[List[str]]) -> int:
rows = len(matrix)
if rows:
cols = len(matrix[0])
else:
cols = 0
dp = [0] * (cols + 1)
maxsq = 0
prev = 0
for i in range(1, rows + 1):
for j in range(1, cols + 1):
temp = dp[j]
if matrix[i - 1][j - 1] == "1":
min_prev = min(dp[j - 1], prev)
min_cur = min(min_prev, dp[j])
dp[j] = min_cur + 1
maxsq = max(maxsq, dp[j])
else:
dp[j] = 0
prev = temp
return maxsq * maxsq
|