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 H 2000000

int left(int i) { return i * 2; }
int right(int i) { return i * 2 + 1; }

int n, A[H + 1];

void maxHeapify(int i) {
	int l, r, largest, tmp;

	l = left(i);
	r = right(i);
	if (l <= n && A[l] > A[i]) largest = l;
	else largest = i;
	if (r <= n && A[r] > A[largest]) largest = r;


	if (largest != i) {
		tmp = A[i];
		A[i] = A[largest];
		A[largest] = tmp;
		maxHeapify(largest);
	}
}

int extract() {
	int max;
	max = A[1];
	A[1] = A[n];
	n--;
	maxHeapify(1);
	return max;
}

void inc(int i, int key) {
	int tmp;
	if (key < A[i]) return;
	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 insert(int k) {
	n++;
	A[n] = -100000000;
	inc(n, k);
}

int main() {

	int i=1, j,k;
	char com[10];

	while (1) {
		scanf("%s", com);
		if (com[2] == 'd') break;
		else if (com[0] == 'i') {
			scanf("%d", &k);
			insert(k);
		}
		else {
			printf("%d\n",extract());
			i--;
		}
	
	}
	
	return 0;
}