33 lines
845 B
Python
33 lines
845 B
Python
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# Time: O(N · H) where H is the maximum height
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# Space: O(1)
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class Solution:
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def trap(self, height: List[int]) -> int:
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maxh = 0
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for h in height:
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maxh = max(h, maxh)
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land_width = len(height)
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output = 0
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for i in range(maxh):
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row_output = 0
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trough_output = 0
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trough_start = -1
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for j in range(land_width):
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# A block is present
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if height[j] >= i + 1:
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row_output += trough_output
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trough_start = j
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trough_output = 0
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elif trough_start >= 0:
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trough_output += 1
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output += row_output
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return output
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