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 C++ (judge verdict: Accepted)

#include<iostream>
#include<cstdio>
#define MAX 2000000+5
using namespace std;
int heap[MAX];
int num;
void maxheapify(int i){
	int largest;
	int left=i*2;int right=i*2+1;
	if(left<=num&&heap[left]>heap[i]){
		largest=left;
	}else{
		largest=i;
	}
	if(right<=num&&heap[largest]<heap[right]){
		largest=right;
	}
	if(largest!=i){
		swap(heap[largest],heap[i]);
		maxheapify(largest);
	}
	return;
}
void insert(int i){
num++;
heap[num]=i;
int t=num;
while(t>1&&heap[t/2]<heap[t]){
	swap(heap[t],heap[t/2]);
	t=t/2;
}
return;
}
void extract(){
	cout<<heap[1]<<endl;
	heap[1]=heap[num];num--;
	maxheapify(1);
	return;
}
int main(){
	char s[10];
	num=0;
	while(scanf("%s",&s)){
		if(s[0]=='i') {
			int i;scanf("%d",&i);insert(i);
		}else if(s[0]=='e'&&s[1]=='x'){
			extract();
		}else break;
			
		}
	}