forked from colonelpanic/dotfiles
50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
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import heapq
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def get_skyline(buildings):
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result = []
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active_buildings = []
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last_index = -1
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def add_entry(index, height):
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last_height = result[-1][1] if result else 0
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if height != last_height:
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result.append([index, height])
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def handle_next_active_building():
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(negative_height, end_index) = heapq.heappop(active_buildings)
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while active_buildings and active_buildings[0][1] <= end_index:
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heapq.heappop(active_buildings)
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new_height = -active_buildings[0][0] if active_buildings else 0
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add_entry(end_index, new_height)
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def add_entry_for_last():
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if active_buildings:
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add_entry(last_index, -active_buildings[0][0])
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for (left_index, right_index, height) in buildings:
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if last_index > -1 and left_index != last_index:
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# We have to do this here inside this if statement to handle the
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# case where multiple building (potentially having different
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# heights) start on the same index.
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add_entry_for_last()
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while active_buildings and active_buildings[0][1] < left_index:
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handle_next_active_building()
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heapq.heappush(active_buildings, (-height, right_index))
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last_index = left_index
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add_entry_for_last()
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while active_buildings:
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handle_next_active_building()
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return result
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if __name__ == '__main__':
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print(get_skyline([[1,9,10],[1,7,15],[5,12,12],[15,20,10],[19,24,8], [26, 100, 100]]))
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