1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3  4 #Author: Minion-Xu 5 #list实现优先队列 6  7 class ListPriQueueValueError(ValueError): 8     pass 9 10 class List_Pri_Queue(object):11     def __init__(self, elems = []):12         self._elems = list(elems)13         #从大到小排序，末尾值最小，但优先级最高，方便弹出且效率为O（1）14         self._elems.sort(reverse=True)15 16     #判断队列是否为空17     def is_empty(self):18         return self._elems is []19 20     #查看最高优先级 O(1)21     def peek(self):22         if self.is_empty():23             raise ListPriQueueValueError("in pop")24         return self._elems[-1]25 26     #弹出最高优先级 O(1)27     def dequeue(self):28         if self.is_empty():29             raise ListPriQueueValueError("in pop")30         return self._elems.pop()31 32     #入队新的优先级 O(n)33     def enqueue(self, e):34         i = len(self._elems) - 135         while i>=0:36             if self._elems[i] < e:37                 i -= 138             else:39                 break40         self._elems.insert(i+1, e)41 42 if __name__=="__main__":43     l = List_Pri_Queue([4,6,1,3,9,7,2,8])44     print(l._elems)45     print(l.peek())46     l.dequeue()47     print(l._elems)48     l.enqueue(5)49     print(l._elems)50     l.enqueue(1)51     print(l._elems)