Priority queue

heapq wrapper class.

Try this in Python

import heapq

class PQ:
    def __init__(self):
        self.h = []

    def push(self, x):
        heapq.heappush(self.h, x)

    def pop(self):
        return heapq.heappop(self.h)

pq = PQ()
pq.push(2)
pq.push(1)
print(pq.pop(), pq.pop())

Key takeaways

• Not thread-safe.
• Lazy decrease-key.
• queue.PriorityQueue.