class disjointset{ public: vector rank,parent,size;

disjointset(int n){
   rank.resize(n+1,0);
   parent.resize(n+1);
   size.resize(n+1);

   for(int i=0;i<n;i++){
      parent[i] = i;
      size[i] = 1;
   }
}

int findUPar(int node){
   if(node == parent[node]){
      return node;
   }
   return parent[node] = findUPar(parent[node]);
}

void unionBySize(int u,int v){
   int ulp_u = findUPar(u);
   int ulp_v = findUPar(v);
   if(ulp_u == ulp_v) return;
   if(size[ulp_u] < size[ulp_v]){
      parent[ulp_u] = ulp_v;
      size[ulp_v]+=size[ulp_u];
   }
   else{
      parent[ulp_v] = ulp_u;
      size[ulp_u]+=size[ulp_v];
   }
}

};

...take the input of the edges and sort them :)

...also take the query in input and sort and accordingly join the edges

struct DSU{ vll parent,size; DSU(ll n){ size.assign(n,1); parent.assign(n,0); fl(i,n){ parent[i]=i; } }

ll upar(ll x){
    if(parent[x]==x)return x;
    return parent[x]=upar(parent[x]);
}

void merge(ll a,ll b){
    a=upar(a),b=upar(b);
    if(a==b)return;
    ll psize=size[a];
    size[a]+=size[b];
    parent[b]=a;
    ans+=(ncr(size[a])-ncr(size[b])-ncr(psize));
} 

};

are you sure you need hint ,this is standard problem

struct DSU{ vll parent,size; DSU(ll n){ parent.resize(n); size.resize(n); fl(i,n){ parent[i]=i; size[i]=i; } }

ll upar(ll x){
    if(parent[x]==x)return x;
    return parent[x]=upar(parent[x]);
}

void merge(ll a,ll b){
    a=upar(a);
    b=upar(b);
    parent[b]=a;
    size[a]+=size[b];
}

};

nake two DSU for m1 and m2 and connect them and also avoid cycle similar to previous question

struct DSU{ vll parent,size; DSU(ll n){ parent.resize(n); size.resize(n); fl(i,n){ parent[i]=i; size[i]=i; } }

ll upar(ll x){
    if(parent[x]==x)return x;
    return parent[x]=upar(parent[x]);
}

void merge(ll a,ll b){
    a=upar(a);
    b=upar(b);
    parent[b]=a;
    size[a]+=size[b];
}

};

try to make highest bit Zero

struct DSU{ vll par,size; DSU(ll n){ par.resize(n); size.resize(n); fl(i,n){ par[i]=i; size[i]=1; } }

ll upar(ll x){
    if(par[x]==x)return x;
    return par[x]=upar(par[x]);
}

void merge(ll a,ll b){
    a=upar(a);b=upar(b);
    if(a==b){
       return;
    }
    par[b]=a;
    size[a]+=size[b];
}

ll sz(ll x){
    return size[upar(x)];
}

};

try to connect min weight node with the all node

struct DSU{ vll par,size; DSU(ll n){ par.resize(n); size.resize(n); fl(i,n){ par[i]=i; size[i]=1; } }

ll upar(ll x){
    if(par[x]==x)return x;
    return par[x]=upar(par[x]);
}

bool merge(ll a,ll b){
    a=upar(a);b=upar(b);
    if(a==b){
       return 0;
    }
    par[b]=a;
    size[a]+=size[b];
    return 1;
}

ll sz(ll x){
    return size[upar(x)];
}

};