Min Heap

#include <cmath>
#include <cstdio>
#include <vector>
#include <map>
#include <iostream>
#include <climits>
#include <algorithm>
using namespace std;

// Solves this problem: https://www.hackerrank.com/challenges/qheap1/problem?isFullScreen=true

const int M = 4e5  + 50;


int heap[M];
int len;

int parent(int i)
{
    return (i-1)/2;
}

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

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

void insert(int x)
{
    int i = len;
    heap[i] = x;
    ++len;
    while(i!=0 && heap[parent(i)] > heap[i])
    {
        swap(heap[i],heap[parent(i)]);
        i = parent(i);
    }
}

void minify(int i)
{
    int l = left(i);
    int r = right(i);
    int smallest = i;
    if(l<len && heap[l] < heap[smallest])
        smallest = l;
    if(r < len && heap[r] < heap[smallest])
        smallest = r;
    if(smallest != i)
    {
        swap(heap[i],heap[smallest]);
        minify(smallest);
    }

}

void del(int x)
{
    int i;
    for(i = 0 ;i< len;i++)
        if(heap[i] == x)
            break;
    heap[i] = INT_MIN;
    while(i != 0 && heap[parent(i)] > heap[i])
    {
        swap(heap[parent(i)],heap[i]);
        i = parent(i);
    }
    heap[0] = heap[len-1];
    --len;
    minify(0);
}

int main()
{
    len = 0;
    int q;
    cin>>q;
    while(q--)
    {
        int t;
        cin>>t;
        if(t == 3)
        {
            cout<<heap[0]<<endl;
            continue;
        }
        int v;
        cin>>v;
        if(t == 1)
            insert(v);
        else
            del(v);
    }
}