Union Find

#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
long long Weight[200013];
multiset <long long> Order;
long long n,q,we,from,to;
long long Father[200013];

int findF(int node){
    if (node==Father[node]) return node;
    return Father[node]=findF(Father[node]);
}

void Forest_merge(int a,int b){
    int f1 = findF(a);
    int f2 = findF(b);
      if (f1==f2) return;
      Father[a] = Father[b];
      Order.erase(Order.find(Weight[f1]));
      Order.erase(Order.find(Weight[f2]));
      Weight[f2] += Weight[f1];
      Order.insert(Weight[f2]);
}

int main(void){
 cin>>n>>q;
 for (int i=1;i<=n;++i){
  cin>>Weight[i];
  Order.insert(Weight[i]);
  Father[i]=i;
 }
 while(q--){
    cin>>from>>to;
    Forest_merge(from,to);
    multiset<long long>::iterator it = Order.begin();
    cout<<*it<<endl;
 }
return 0;
}