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>
#include <stdlib.h>
#include <string.h>

#define MAX 2000000
#define INFTY 999999

int H, A[MAX+1];

void swap(int A,int B){

  int t;
  t=A;
  A=B;
  B=t;
  
}

void maxHeapify(int i) {

  int l,r,largest;
  int t;
  l=2*i;
  r=2*i+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){
    t=A[i];
    A[i]=A[largest];
    A[largest]=t;
    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) {

  int t;

  if ( key < A[i] ) return;
  A[i] = key;
  while ( i > 1 && A[i / 2] < A[i] ) {
    
    t=A[i];
    A[i]=A[i/2];
    A[i/2]=t;
    i = i / 2;
  }
  
}

/*
void insert(int key) {

  H++;
  A[H] = -INFTY;
  increaseKey(H, key);
  
}
*/

int print(char com[]){

  int key;
  
  if ( com[0] == 'e' && com[1] == 'n' ) return -1;
  if ( com[0] == 'i' ) {

    scanf("%d", &key);

    H++;
    A[H] = -INFTY;
    increaseKey(H, key);

  }
  else {
    printf("%d\n", extract());
  }

  return 0;
}

int main() {

  int key;
  char com[10];

  while ( 1 ) {
    scanf("%s", com);
    if(print(com)==-1) break;    
  }
  return 0;
  
}