118 lines
2.8 KiB
Python
118 lines
2.8 KiB
Python
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#!/usr/bin/python
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# -*- coding: UTF-8 -*-
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import math
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class QueueNode:
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def __init__(self, priority, data=None):
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assert type(priority) is int and priority >= 0
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self.priority = priority
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self.data = data
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def __repr__(self):
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return str((self.priority, self.data))
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class PriorityQueue:
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def __init__(self, capacity=100):
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self._capacity = capacity
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self._q = []
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self._length = 0
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def enqueue(self, priority, data=None):
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if self._length >= self._capacity:
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return False
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new_node = QueueNode(priority, data)
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self._q.append(new_node)
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self._length += 1
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# update queue
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nn = self._length - 1
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while nn > 0:
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p = (nn - 1) // 2
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if self._q[nn].priority < self._q[p].priority:
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self._q[nn], self._q[p] = self._q[p], self._q[nn]
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nn = p
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else:
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break
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return True
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def dequeue(self):
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if self._length <= 0:
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raise Exception('the queue is empty....')
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self._q[0], self._q[-1] = self._q[-1], self._q[0]
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ret = self._q.pop()
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self._length -= 1
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if self._length > 1:
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# update queue
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lp = (self._length - 2) // 2
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idx = 0
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while idx <= lp:
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lc = 2 * idx + 1
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rc = lc + 1
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if rc <= self._length - 1:
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tmp = lc if self._q[lc].priority < self._q[rc].priority else rc
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else:
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tmp = lc
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if self._q[tmp].priority < self._q[idx].priority:
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self._q[tmp], self._q[idx] = self._q[idx], self._q[tmp]
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idx = tmp
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else:
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break
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return ret
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def get_length(self):
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return self._length
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@staticmethod
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def _draw_heap(data):
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"""
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格式化打印
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:param data:
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:return:
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"""
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length = len(data)
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if length == 0:
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return 'empty'
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ret = ''
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for i, n in enumerate(data):
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ret += str(n)
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# 每行最后一个换行
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if i == 2 ** int(math.log(i + 1, 2) + 1) - 2 or i == len(data) - 1:
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ret += '\n'
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else:
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ret += ', '
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return ret
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def __repr__(self):
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def formater(node):
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assert type(node) is QueueNode
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return node.priority, node.data
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data = list(map(formater, self._q))
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return self._draw_heap(data)
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if __name__ == '__main__':
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pq = PriorityQueue()
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pq.enqueue(5, 'Watch TV')
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pq.enqueue(2, 'Learning')
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pq.enqueue(10, 'Go Sleep')
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pq.enqueue(0, 'Go Home')
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pq.enqueue(7, 'Mobile Games')
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print(pq)
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while pq.get_length() > 0:
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print(pq.dequeue())
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