Number of Visible People in a Queue LeetCode solution in Python

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# Runtime: 2162 ms (Top 20.79%) | Memory: 30.1 MB (Top 6.96%)
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class Solution:
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    def canSeePersonsCount(self, heights: List[int]) -> List[int]:
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        ans = []
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        stack = []
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        n = len(heights)
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        for i in range(n - 1, -1, -1):
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            if len(stack) == 0:
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                ans.append(0)
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                stack.append(heights[i])
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            else:
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                if heights[i] < stack[-1]:
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                    ans.append(1)
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                    stack.append(heights[i])
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                else:
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                    ctr = 0
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                    while len(stack) > 0 and stack[-1] < heights[i]:
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                        ctr += 1
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                        stack.pop()
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                    if len(stack) == 0:
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                        ans.append(ctr)
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                    else:
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                        ans.append(ctr + 1)
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                    stack.append(heights[i])
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        return ans[::-1]