Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

Priority Queue

A priority queue is a data structure which maintains a set $S$ of elements, each of with an associated value (key), and supports the following operations:

$insert(S, k)$: insert an element $k$ into the set $S$

$extractMax(S)$: remove and return the element of $S$ with the largest key

Write a program which performs the $insert(S, k)$ and $extractMax(S)$ operations to a priority queue $S$.
The priority queue manages a set of integers, which are also keys for the priority.

Input

Multiple operations to the priority queue $S$ are given. Each operation is given by "insert $k$", "extract" or "end" in a line. Here, $k$ represents an integer element to be inserted to the priority queue.

The input ends with "end" operation.

Output

For each "extract" operation, print the element extracted from the priority queue $S$ in a line.

Constraints

The number of operations $\leq 2,000,000$

$0 \leq k \leq 2,000,000,000$

Sample Input 1

insert 8
insert 2
extract
insert 10
extract
insert 11
extract
extract
end

Sample Output 1

8
10
11
2

Solution in JAVA (judge verdict: Wrong Answer)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	static List<Integer> Queue = new ArrayList<Integer>();

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		List<Integer> Queue = new ArrayList<Integer>();
		int flag = 1;
		while (flag > 0) {
			String s = sc.next();
			if (s.equals("insert")) {
				int k = sc.nextInt();
				Queue.add(k);
			}
			else if (s.equals("extract")) {
				System.out.println(extractMax());
			}
			else {
				flag = 0;
			}
		}
	}
	
	public static int extractMax() {
		int max = 0;
		for (int i = 0; i < Queue.size(); i++) {
			int tmp = Queue.get(i);
			System.out.println(tmp);
			if (tmp > max) {
				max = tmp;
			}
		}
		return max;
	}

}