class Solution(object):
    def largestRectangleArea(self, heights):
        """
        :type heights: List[int]
        :rtype: int
        """
        heights.append(0)
        stack = [-1]
        ans = 0
        for i in range(len(heights)):
            while heights[i] < heights[stack[-1]]:
                h = heights[stack.pop()]
                w = i - stack[-1] - 1
                ans = max(ans, h * w)
            stack.append(i)
        heights.pop()
        return ans

obj = Solution()
# print(obj.largestRectangleArea([2,1,5,6,2,3])) # 10
# print(obj.largestRectangleArea([2,4])) # 4
# print(obj.largestRectangleArea([0,9])) # 9
# print(obj.largestRectangleArea([0,0,0])) # 0
# print(obj.largestRectangleArea([2,1,2])) # 3
# print(obj.largestRectangleArea([1,2,2])) # 4
# print(obj.largestRectangleArea([0,2,0])) # 2
# print(obj.largestRectangleArea([5,4,1,2])) # 8
# print(obj.largestRectangleArea([2,0,2])) # 2
# print(obj.largestRectangleArea([1,2,3,4,5])) # 9
# print(obj.largestRectangleArea([4,2,0,3,2,5])) # 6