# What is the optimal way to solve FLOW004 or LUCKYFOUR?

I’ve solved the FLOW004 with the following code. However I’m unhappy with the solution I’ve come up with. I’m just getting started hence don’t know the tools to solve it in a better way.

``````#include <bits/stdc++.h>

using namespace std;

int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t;
cin>>t;
while(t--)
{
int n, n1, n2;
cin>>n;

n1 = n%10;
n/=10;
while(n)
{
n2 = n%10;
n/=10;

}

cout<<n1+n2<<"\n";

}

}
``````

Perhaps a better method will be to treat the number as a string and then take the first and last element? This will eliminate the need of a loop and make it faster for longer numbers, giving it a constant complexity instead of O(n);
Please help. Thanks!

Inputting takes O(log(n)) time, and so does your code.
But you can alternatively do this

``````#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t;
cin>>t;
while(t--){
string n;
cin>>n;
cout<<n[0] + n[n.size()-1] - 2*'0'<<"\n";
}
}
``````