优先级队列PriorityQueue

class PriorityQueue:
    def __init__(self):
        self.heaplist = [(0, None)]
        self.currentsize = 0

    def perceedUp(self,index):
        while index // 2 > 0:
            if self.heaplist[index][0] < self.heaplist[index // 2][0]:
                self.heaplist[index // 2], self.heaplist[index] = self.heaplist[index], self.heaplist[index // 2]
            index = index // 2

    def insert(self, item):
        self.heaplist.append(item)
        self.currentsize += 1
        self.perceedUp(self.currentsize)

    def perceedDown(self, index):
        while index * 2 <= self.currentsize:
            minChildIndex = self.minChild(index)
            if self.heaplist[minChildIndex][0] < self.heaplist[index][0]:
                self.heaplist[minChildIndex], self.heaplist[index] = self.heaplist[index], self.heaplist[minChildIndex]
                index = minChildIndex
            else:
                break

    def minChild(self, index):
        if index * 2 + 1 > self.currentsize:
            return index * 2
        else:
            if self.heaplist[index * 2][0] < self.heaplist[index * 2 + 1][0]:
                return index * 2
            else:
                return index * 2 + 1

    def delMin(self):
        result = self.heaplist[1][1]
        self.heaplist[1] = self.heaplist[self.currentsize]
        self.currentsize -= 1
        self.heaplist.pop()
        self.perceedDown(1)
        return result

    def buildHeap(self, li):
        i = len(li) // 2
        self.heaplist = [(0, None)] + li
        self.currentsize = len(li)
        while i:
            self.perceedDown(i)
            i -= 1


if __name__ == '__main__':
    pq = PriorityQueue()
    pq.insert((2,'zhangsan'))
    pq.insert((5, 'lisi'))
    pq.insert((1, 'wangwu'))
    pq.insert((6, 'aaa'))
    pq.insert((9, 'bbb'))
    print(pq.delMin())
    print(pq.delMin())
    print(pq.delMin())

输出:

wangwu
zhangsan
lisi

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