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 N 2000000
 
 
int h = 0;
 
void MaxHeapify(int *a, int i){
  int left, right, large, tmp;
  
  if(i * 2 <= h) 
    left = i * 2;
  else left = i;
  
  if(i * 2 + 1 <= h) 
    right = i * 2 + 1;
  
  else right = i;
  
  
  if(left < h + 1 && a[left] > a[i]) 
    large = left;
  else large = i;
  
  if(right < h + 1 && a[right] > a[large]) 
    large = right;
   
  if(large != i){
    tmp = a[i];
    a[i] = a[large];
    a[large] = tmp;
    MaxHeapify(a, large);
  }
}
 
void Insert(int *a, int key){
  int i, tmp;
 
  h++;
  i = h;
  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 Extract(int *a){
  int max;
 
  max = a[1];
  a[1] = a[h];
  h--;
  MaxHeapify(a, 1);
 
  printf("%d\n", max);
}

int main(void){
 
 int a[N], key;
  int i = 0, j;
  char c[8];
 
  while( 1 ){
      scanf("%s", c);
      if(c[2] == 'd') break;
      else if(c[0] == 'i'){
   
	scanf("%d", &key);
	Insert(a, key);
      }
      else Extract(a);
  }
 
  return 0;
}