HackerEarth Killjee and cities problem solution

In this HackerEarth Killjee and cities problem solution Killjee lives in Codaland. Codaland has n cities and m bidirectional roads connecting these cities, but not all cities are connected. Now the President of Codaland has passed an order to build q new roads one by one connecting two different cities.

Killjee wonders how many new roads are needed to connect all the cities of Codaland after construction of each road as per President’s plan.

Note:- There can be multiple number of roads between two same cities.

#include<bits/stdc++.h>
using namespace std;
int rnk[1000005],par[1000005];
int findparent(int val)
{
    if(par[val]==val)return val;
    return par[val]=findparent(par[val]);
}
void makeunion(int a,int b)
{
    int para=findparent(a);
    int parb=findparent(b);
    if(para==parb)return;
    else
    {
        if(rnk[para]<rnk[parb])
            par[parb]=para;
        else if(rnk[parb]<rnk[para])
            par[para]=parb;
        else
        {
            par[parb]=para;
            rnk[para]++;
        }
    }
}
int main()
{
    int n,m,q,s;
    cin>>n>>m>>s;
    assert(n>=1 && n<=1e6);
    assert(m>=0 && m<=1e6);
    assert(s==2);
    for(int i=1;i<=1000000;i++)par[i]=i;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        assert(x>=1 && x<=n);
        assert(y>=1 && y<=n);
        assert(x!=y);
        makeunion(x,y);
    }
    int com=0;
    for(int i=1;i<=n;i++)if(par[i]==i)com++;
    cin>>q>>s;
    assert(q>=1 && q<=1e6);
    assert(s==2);
    while(q--)
    {
        int x,y;
        cin>>x>>y;
        assert(x>=1 && x<=n);
        assert(y>=1 && y<=n);
        assert(x!=y);
        if(findparent(x)!=findparent(y)){makeunion(x,y);com--;}
        cout<<com-1<<" ";
    }
    return 0;
}