Naruto and One Shot Graph

Hi, I am new to graphs, and I tried the question:
https://www.codechef.com/problems/ECAUG207

The approach is as follows:
each node will have the maximum sum of its children’s connected components
tempans will be the minimum of that value for the graph, and that will be the answer

#include <iostream>
#include<vector>
#define ll long long
using namespace std;
vector<long long int> arr[100001];

long long int dfs(long long int parent,long long int child){
    long long int ans=1;
    for(long long int i: arr[child]){
        if(i==parent) continue;
        else{
            ans+=dfs(child, i);
        }
    }
    return ans;
}

int main()
{
   long long int t;cin>>t;
   while(t--){
       long long int n;cin>>n;
       for(long long int i=0;i<n;i++) arr[i]={};
       for(long long int i=0;i<n-1;i++){
           long long int a,b;
           cin>>a>>b;
           arr[a-1].push_back(b-1);
           arr[b-1].push_back(a-1);
       }
       long long int ans=0, maxi=10000000;
       for(long long int i=0;i<n;i++){
           long long int temp=0,tempans=0;
           for(long long int j=0;j<arr[i].size();j++){
               temp=dfs(i,arr[i][j]);
            //   cout<<"dfs "<<i<<" "<<j<<" "<<temp<<endl;
               tempans=max(tempans,temp);
           }
           if(tempans<maxi) {maxi=tempans; ans=i;}
       }
       cout<<ans+1<<" "<<maxi<<endl;
   }
}