https://www.codechef.com/PBK12020/problems/ITGUY18/

Can anyone help me how to solve this problem?

**To make it easy to understand look at this image first**

So ,The total for any NxN square is (N squared + N-1 squared + N-2 sqaured down to 1 when N=1.

so we need all the summation of all the sqaures 1 to N.

And For the Sum Of the First N Squares is

S = n(n+1)(2n+1)/6

[You read it about here. its just maths]

(https://math.stackexchange.com/questions/183316/how-to-get-to-the-formula-for-the-sum-of-squares-of-first-n-numbers)

thats it .hope it helps.

**My code**

```
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
ll t;
cin>>t;
while(t--)
{
ll N,sum=0;
cin>>N;
sum=(N * (N + 1) * (2*N + 1)) / 6 ;//sum of n squares
cout<<sum<<endl;
}
return 0;
}
```

1 Like

Thanks, Bro.Got it.

i was thinking abt it …

thanks bro