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>
void maxheap(int* , int , int);
void insert(int*, int, int);
int main(){
  int value,array[2000000],size=0,max;
  char command[10];
  while(1){
    scanf("%s",command);
    if(command[0]=='e' && command[1]=='n') break;  /* It means end*/
    if(command[0]=='e'){           /* It means extract*/
      if(size==0) break;
      max=array[1];
      array[1]=array[size];
      size--;
      
      
      maxheap(array,1,size);
      printf("%d\n",max);
     
    }
    if(command[0]=='i'){    /* It means insert */
      size++;
      scanf("%d",&value);
      insert(array,size,value);
    }
  }
  return 0;
}
      
void maxheap(int *array, int i, int num){
  int left,right,max,value;
  left=i*2;
  right=i*2+1;
  if(left<=num &&  array[left]>array[i]) max=left;
  else max=i;
  if(right<=num && array[right]>array[max]) max=right;
  if(max!=i){
    value=array[i];     /* exchange array[i] and array[max] */
    array[i]=array[max];
    array[max]=value;
    maxheap(array,max,num);
  }
}

void insert(int *array, int size, int value){
  int change;
  array[size]=value;
  while(size>1 && array[size/2] < array[size]){
    change=array[size];
    array[size]=array[size/2];
    array[size/2]=change;
    size=size/2;
  }
}