Spoj ap2 getting wrong output

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C++14

I was solving arithmatic progression question SPOJ.com - Problem AP2[^]
Logic-> first term + last term = third term + third last
sum=n/2(first term+last term)
I tried many test cases it is passing all ?Can any one help me whats wrong with my code?
Its look like it may be some kind of overflow?

What I have tried:

#include<iostream>
using namespace std;
int main(){
    int t;
    cin>>t;
    while(t--){
        long long int third;
        long long int thirdlast;
        long long int sum;
        cin>>third>>thirdlast>>sum;
        long long int n=(2*sum)/(third+thirdlast);
        long long int d= (thirdlast-third)/(n-5);  //(2*thirdlast-third*n+3*third)/(5-n);
        long long int a=(third-2*d);
        //cout<<n<<endl;
        //cout<<d<<endl;
        //int d=0;
        for(int i=1;i<=n;i++){
            long long int temp=d*(i-1);
          //  int t=a+d;
            cout<<a+temp<<" ";


        }
        cout<<endl;

    }
}