Project Euler #2: Even Fibonacci numbers

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    #include <map>
    #include <set>
    #include <list>
    #include <cmath>
    #include <ctime>
    #include <deque>
    #include <queue>
    #include <stack>
    #include <string>
    #include <bitset>
    #include <cstdio>
    #include <limits>
    #include <vector>
    #include <climits>
    #include <cstring>
    #include <cstdlib>
    #include <fstream>
    #include <numeric>
    #include <sstream>
    #include <iostream>
    #include <algorithm>
    #include <unordered_map>
    
    using namespace std;
    
    
    int main(){
        int t;
        cin >> t;
        for(int a0 = 0; a0 < t; a0++){
            long n;
            cin >> n;
            long long int f1 = 1,f2 = 2,f = 0, sum = 0;
            while(f1 < n)
            {
                if(f1 % 2 == 0)
                {
                    sum += f1;
                }
                f = f1 + f2;
                f1 = f2;
                f2 = f;
                //cout << f1 << endl;
            }
            cout << sum << endl;
        }   return 0;
    }