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<stdio.h>
 
#define M 2000001
#define INFTY (1<<30)
 
int H, A[M];
 
void maxHeapify(int i){
    int l, r, biggest, tmp;
    
    l = 2 * i;
    r = 2 * i + 1;

    if(l <= H && A[l] > A[i]) biggest=l;
    else biggest=i;
    
    if(r <= H && A[r] > A[biggest]) biggest=r;
    if(biggest != i){
        tmp = A[i];
        A[i] = A[biggest];
        A[biggest] = tmp;
        maxHeapify(biggest);
    }
}
 
int extract(){
    int maxv;
    if(H < 1)return -INFTY;
    maxv = A[1];
    A[1] = A[H--];
    maxHeapify(1);
    return maxv;
}
 
void increKey(int i, int key){
    int tmp;
    if(key < A[i]) return;
    A[i] = key;
    while(i > 1 && A[i/2] < A[i]){
        tmp = A[i];
        A[i] = A[i/2];
        A[i/2] = tmp;
        i = i/2;
    }
}
 
void insert(int key){
    H++;
    A[H] = -INFTY;
    increKey(H,key);
}
 
int main(){
    int key;
    char com[10];
    while(1){
        scanf("%s", com);
        if(com[0]=='e' && com[1]=='n'){
            break;
        }
        if(com[0]=='i'){
            scanf("%d", &key);
            insert(key);
        }
        else printf("%d\n", extract());
    }
    
    return 0;
}