50 lines
1.2 KiB
Python
50 lines
1.2 KiB
Python
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class BinaryHeap:
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def __init__(self, n):
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self.heap = [0] * n
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self.size = 0
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def remove_min(self):
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removed = self.heap[0]
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self.size -= 1
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self.heap[0] = self.heap[self.size]
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self._down(0)
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return removed
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def add(self, value):
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self.heap[self.size] = value
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self._up(self.size)
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self.size += 1
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def _up(self, pos):
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while pos > 0:
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parent = (pos - 1) // 2
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if self.heap[pos] >= self.heap[parent]:
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break
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self.heap[pos], self.heap[parent] = self.heap[parent], self.heap[pos]
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pos = parent
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def _down(self, pos):
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while True:
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child = 2 * pos + 1
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if child >= self.size:
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break
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if child + 1 < self.size and self.heap[child + 1] < self.heap[child]:
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child += 1
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if self.heap[pos] <= self.heap[child]:
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break
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self.heap[pos], self.heap[child] = self.heap[child], self.heap[pos]
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pos = child
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def test():
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h = BinaryHeap(10)
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h.add(3)
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h.add(1)
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h.add(2)
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print(h.remove_min())
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print(h.remove_min())
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print(h.remove_min())
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test()
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