https://www.acmicpc.net/problem/11279
최소힙에서 item 값만 음수로 전환시키면된다.
import heapq
import sys
n = int(sys.stdin.readline())
heap = []
for i in range(n):
num = int(sys.stdin.readline())
if num == 0:
if len(heap) == 0:
print(0)
else:
print(-heapq.heappop(heap))
else:
heapq.heappush(heap, -num)