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 <string.h>
int q[2000000];
void swap(int i, int j) {
  int t;
  t=q[i];
  q[i]=q[j];
  q[j]=t;
}
int main(void) {
  int k,s=0,i,pr,l,r;
  char com[2];
  while (1) {
    scanf("%s%d", com,&k);
    if(!strncmp(com,"en",2)) break;
    if(com[0]=='i'){
      q[i=s]=k;
      while (i>0 && q[i]>q[pr=(i-1)/2]) {
        swap(i,pr);
        i=pr;
      }
      ++s;
    } else {
      printf("%d\n", q[0]);
      q[i=0]=q[--s];
      --q[s];
      while ((l=i*2+1)<s) {
        if ((r=l+1)<s && q[r] > q[l]) l=r;
        if (q[i] < q[l]) swap(i,l);
        i=l;
      }
    }
  }
  return 0;
}