Problem:
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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: Time Limit Exceeded)

import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String n = scan.next();
        comp c = new comp();
        PriorityQueue<Integer> set = new PriorityQueue<>(2000000, c);
        while (!n.equals("end")){
            if(n.equals("insert")){
                int x = scan.nextInt();
                set.add(x);
            }
            else{
                System.out.println(set.poll());
            }
            n = scan.next();
        }
    }
    static class comp implements Comparator<Integer>{
        public int compare(Integer x, Integer y){
            if(x > y){
                return -1;
            }
            else{
                return 1;
            }
        }
    }
}