2-4-1.cpp

#include <bits/stdc++.h>
using namespace std;

const int MAXS = 1 << 10;
int heap[MAXS], sz = 0;

void push(int x) {
	int i = sz++;
	while(i > 0) {
		int p = (i - 1) / 2;
		if (heap[p] <= x) break;
		heap[i] = head[p];
		i = p;
	}
	heap[i] = x;
}

int pop() {
	int ret = heap[0];
	int x = heap[--sz];
	while(i * 2 + 1 < sz) {
		int a = i * 2 + 1, b = i * 2 + 2;
		if (b < sz && heap[b] < heap[a]) a = b;
		if (heap[a] >= x) break;
		heap[i] = heap[a];
		i = a;
	}
	heap[i] = x;
	return ret;
}