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: Wrong Answer)

import java.util.Scanner;
public class Main{
	static int[]heap;
    static int MAXHEAP=2000000;
    static int n=0;
	public static void main(String[] args) {
		// TODO Auto-generated method stub
	    int i;
	    String hz;
		heap=new int[MAXHEAP+1];
       Scanner sca= new Scanner(System.in);
       for(i=0;i<2000000;i++){
	   hz=sca.next();
	   if(hz.equals("insert")){
	    maxHeapInsert(sca.nextInt());
	   }
	   if(hz.equals("extract")){
	       System.out.println(extract()+" "+heap[1]);
	   }
	   if(hz.equals("end"))break;
       }
	}
	public static void maxHeapify(int i){
		int l=i*2,r=i*2+1,largest,hz;
		if(i<=n&&heap[l]>heap[i]){
			largest=l;
		}else{
			largest=i;
		}
		if(r<=n&&heap[r]>heap[largest])largest=r;
		if(largest!=i){
			hz=heap[largest];
			heap[largest]=heap[i];
			heap[i]=hz;
			maxHeapify(largest);
		}
	}
    public static void maxHeapInsert(int key){
	n++;
	heap[n]=Integer.MIN_VALUE;
	heapIncreaseKey(n,key);
    }
    public static void heapIncreaseKey(int i,int key){
	int hz;
	if (key<heap[i])return;
	heap[i]=key;
	while(i>1&&heap[i/2]<heap[i]){
	    hz=heap[i/2];
	    heap[i/2]=heap[i];
	    heap[i]=hz;
	    i/=2;
	}
    }
    public static int extract(){
	int max;
	if(n==0)return -1;
	max=heap[1];
	heap[1]=heap[n];
	n--;
	maxHeapify(1);
	return max;
    }

}