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 C (judge verdict: Accepted)

#include<stdio.h>

#define MAX 2000000
#define INFTY (1<<30)

int H, A[MAX+1];

void maxHeapify(int i){
    int l, r, largest;
    l=2*i;
    r=l+1;

    if(l <= H && A[l] > A[i]){
        largest=l;
    }
    else{
        largest=i;
    }
    if(r<=H && A[r] > A[largest]){
        largest=r;
    }
    if(largest!=i){
        int temp;
        temp=A[i];
        A[i]=A[largest];
        A[largest]=temp;
        maxHeapify(largest);
    }
}

int extract(){
    int maxv;
    if(H<1){
        return -INFTY;
    }
    maxv=A[1];
    A[1]=A[H--];
    maxHeapify(1);

    return maxv;
}

void increaseKey(int i, int key){
    if(key<A[i]){
        return;
    }
    A[i]=key;
    while(i>1 && A[i/2]<A[i]){
        int temp;
        temp=A[i];
        A[i]=A[i/2];
        A[i/2]=temp;
        i=i/2;
    }
}

void insert(int key){
    H++;
    A[H]=-INFTY;
    increaseKey(H, key);
}


int main(void){
    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;
}