Plz help in "RECNDNUM" getting WA

#include<iostream>
using namespace std;
const int o=1e9+7;
unsigned long long int func(int k)
{
    unsigned long long int sum=0;
    sum=(k%o)*((k+1)%o);
    return sum;
}
int main()
{
    long long int t;
    cin>>t;
    while(t--){
    unsigned long long int n,k;
    cin>>n>>k;
    if(n==0){
        k=k-1;
        cout<<func(k)<<endl;
    }
    else{unsigned long long int time=0;
    if(k%2==1)
    {
        k=k-1;
        time=time+k%o;
    }
    unsigned long long int c=((k/2)+n-1)%o;
    time=time+func(c)+n;
    cout<<time<<endl;
}
}
return 0;
}