최소힙 - 배열 구현

#include <iostream>
#include <vector>
 
using namespace std;
 
int heap[2 * 100000 + 1], heap_idx = 0;
 
int pop() {
    int result = heap[1];
 
    int tmp = heap[1];
    heap[1] = heap[heap_idx];
    heap[heap_idx] = tmp;
 
    heap_idx--;
 
    int parent = 1;
    int child = parent * 2;
 
    if (child + 1 <= heap_idx) {
        //가장 마지막 노드 
        child = heap[child] < heap[child + 1] ? child : child + 1;
    }
 
    while (child <= heap_idx && heap[parent] > heap[child]) {
        int tmp = heap[parent];
        heap[parent] = heap[child];
        heap[child] = tmp;
 
        parent = child;
        child *= 2;
        if (child + 1 <= heap_idx) child = heap[child] < heap[child + 1] ? child : child + 1;
    }
 
    return result;
}
void push(int data) {
    heap[++heap_idx] = data;
 
    int child = heap_idx;
    int parent = heap_idx / 2;
 
    while (child > 1 && heap[parent] > heap[child]) {
        int tmp = heap[parent];
        heap[parent] = heap[child];
        heap[child] = tmp;
 
        child = parent;
        parent = child / 2;
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
 
    int n;
    cin >> n;
 
    for (int i = 0; i < n; i++) {
        int order;
        cin >> order;
        if (!order) {
            // 배열에 값을 넣는다.
            if (heap_idx >= 1)
                cout << pop() << '\n';
            else cout <<  0 << '\n';
        }
        else push(order);
    }
    return 0;
}