Calculating subtree size in O(n) using DFS.cpp

// Calculating subtree size in O(n) using DFS
#include <bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define ll long long int
#define vi vector<int>
#define vii vector<int, int>
#define vc vector<char>
#define vl vector<ll>
#define mod 1000000007 
#define INF 1000000009
using namespace std;


int main()
{
     ios_base::sync_with_stdio(0);
     cin.tie(0);
     cout.tie(0);
     int t;
     t = 1;
     cin >> t;
     while(t--) {
     	
     }
     
     
     
     
     
return 0;
}