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: Wrong Answer)

#include<stdio.h>
#define N 500000
  
int n;
int p(int i){
  return i/2;
}
 
int l(int i){
  return 2*i;
}
  
int r(int i){
  return 2*i+1;
}   
  
  
void maxheapify(int h[],int i){
  int largest=0,aa,le,ri;
  le = l(i);
  ri = r(i);
  if(le <= n && h[le] > h[i]){
    largest = le;
  }
  else{
    largest = i;
   }
  if(ri <= n && h[ri] > h[largest]){
    largest = ri;
  }
  if(largest != i){
    aa = h[i];
    h[i] = h[largest];
    h[largest] = aa;
    maxheapify(h,largest);
  }
}
 
 void buildMaxHeap(int  h[]){
  int i;
  for(i = (n/2); i > 0; i--){
    maxheapify(h,i);
  }
}


void heapIncreaseKey(int A[], int i, int key){
  int tmp;
  if (key < A[i]){
    return; 
  }
 
  A[i] = key;
  while (i > 1 && A[p(i)] < A[i]){
    tmp = A[i];
    A[i] = A[p(i)];
    A[p(i)] = tmp;
    i = p(i);
  }
}

 
void maxHeapInsert(int A[], int key){
  n = n + 1;
  A[n] = -1;
  heapIncreaseKey(A, n, key);
}
 


int heapExtractMax(int A[]){
  int max;
  if(n < 1)
    return 0; 
  max = A[1];
  A[1] = A[n];
  n = n - 1;
  maxheapify(A, 1);
  return max;
}
    
  
int main(){
  int i,w;
  int S[N];
  char c[30];

  for(i = 1;i < N;i++){
    scanf("%s",c);

  if(strcmp(c,"end")==0){
      break;
    }
 
    if(c[0]=='i'){
      scanf("%d",&w);
      maxHeapInsert(S,w);
    }
 
    else{
      printf("%d\n",heapExtractMax(S));
    }
  }

  return 0;
}