[백준] 1927번 최소 힙 (silver 2

import java.io.*;
import java.util.*;

public class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
        Queue<Integer>que=new PriorityQueue<>();
        int n=Integer.parseInt(br.readLine());
        for(int i=0; i<n; i++){
            int temp=Integer.parseInt(br.readLine());
            if(temp==0){
                if(que.isEmpty()){
                    bw.write("0\n");
                }
                else{
                    bw.write(que.poll()+"\n");
                }
            }
            else{
                que.offer(temp);
            }
        }
        bw.flush();
    }
}