cookbook 1.5
本帖最后由 大马强 于 2022-1-17 09:31 编辑实现优先级队列
问题描述：
希望给定一个可以设置优先级排序的序列，pop的顺序优先返回优先级最高的元素
借助heapq库实现
class priorityqueue():
def __init__(self) -> None:
self._queue = []
self._index = 0
def push(self, item, prority):
heapq.heappush(self._queue, (-prority, self._index, item))# -prority heapq中数值越小优先级越高，类似堆
self._index += 1
def pop(self):
return heapq.heappop(self._queue)[-1]
class Item():
def __init__(self, name) -> None:
self.name = name
def __repr__(self) -> str:
return "Item({!r})".format(self.name)
q = priorityqueue()
q.push(Item("foo"), 1)
q.push(Item("coo"), 4)
q.push(Item("voo"), 5)
q.push(Item("boo"), 1)
q.push(Item("noo"), 3)
(-5, 2, Item('voo'))
(-4, 1, Item('coo'))
(-3, 4, Item('noo'))
(-1, 0, Item('foo'))
(-1, 3, Item('boo'))
[*]比较的原理是相应下标依次对比，先比tuple tuple...., []和{}比较原理一样
[*]同优先级按照其push顺序来排序
[*]三元元组形式是为了进行方便的比较
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