# 85. Maximal Rectangle
"""
given a 'rows * cols' binary 'matrix' filled with 0's and 1's, find the
largest rectangle containing only 1's and return its area.
"""
class Solution(object):
def maximalRectangle(self, matrix):
"""
:type matrix: List[List[str]]
:rtype: int
"""
if not matrix:
return 0
n, m = len(matrix), len(matrix[0])
heights, ans = [0] * (m + 1), 0
for i in matrix:
for j in range(m):
heights[j] = heights[j] + 1 if i[j] == "1" else 0
stack = []
for j in range(len(heights)):
while stack and heights[j] < heights[stack[-1]]:
h = heights[stack.pop()]
w = j if not stack else j - stack[-1] - 1
ans = max(ans, h * w)
stack.append(j)
return ans
if __name__ == "__main__":
obj = Solution()
print(
obj.maximalRectangle(
matrix=[
["1", "0", "1", "0", "0"],
["1", "0", "1", "1", "1"],
["1", "1", "1", "1", "1"],
["1", "0", "0", "1", "0"],
]
)
)
print(obj.maximalRectangle(matrix=[["0"]]))
print(obj.maximalRectangle(matrix=[["1"]]))
