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>
#include <string.h>
#define SIZE 2000000+1

void insert(int);
int extractMax();
void maxHeapify(int);
void swap(int *,int *);

int heep_size=1;
int A[SIZE];

int main(){
  char order[8];
  int n;

  while(1){
    scanf("%s",order);
    
    if(strcmp(order,"insert") == 0){
      scanf("%d",&n);
      insert(n);
    }
    
    else if(strcmp(order,"extract") == 0){
      int ma;
      ma = extractMax();
      printf("%d\n",ma);
    }
    
    else if(strcmp(order,"end") == 0){
      break;
    }  
  }

  return 0;
  
}

int extractMax(){
  int origin,ma;
  origin = 1;
  ma = A[origin];
  A[origin] = A[heep_size];
  heep_size--;
  maxHeapify(origin);

  return ma;
}

void insert(int key){
  int par,pos;
  heep_size++;
  A[heep_size] = key;
  pos = heep_size;
  par = pos/2;

  while(pos > 1 && A[pos] > A[par]){
    swap(&A[par],&A[pos]);
    pos = par;
    par /= 2;
  }
}
 
void swap(int *a,int *b){
  
  int tmp;
  tmp = *a;
  *a = *b;
  *b = tmp;
  
}

void maxHeapify(int i){
  int left,right,maximum;
  left = i*2;
  right = i*2+1;
  if(left <= heep_size && A[left] > A[i])
    maximum = left;
  else maximum = i;
  
  if(right <= heep_size && A[right] > A[maximum])
    maximum = right;
  
  if(maximum != i){
    swap(&A[i],&A[maximum]);
    maxHeapify(maximum);
  }

}