[백준] 1927 최소 힙

문제링크: www.acmicpc.net/problem/1927

1927번: 최소 힙

import java.io.*;
import java.util.*;
public class Main {

	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int loop = Integer.parseInt(br.readLine());
		PriorityQueue<Integer> q = new PriorityQueue<Integer>();
		for(int i=0;i<loop;i++) {
			int num = Integer.parseInt(br.readLine());
			if(num==0) {
				if(q.isEmpty()) {
					System.out.println(0);
				}else {
					System.out.println(q.peek());
				}
				q.poll();
			}else {
				q.offer(num);
			}
		}
	}

}