hdu 2817 A sequence of numbers

#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <iostream>

using namespace std;

const int mod=200907;


long long quickpow(long long m,long long n)
{
    long long ans=1;
    while(n)
    {
        if(n&1)
            ans=(ans%mod)*(m%mod)%mod;
        n=n>>1;
        m=(m*m)%mod;
    }
    return ans;
}
int main()
{
    long long n,a,b,c,d,q,k,ans;
    cin>>n;
    while(n--)
    {
        cin>>a>>b>>c>>k;
        if(a+c==2*b)
        {
            d=b-a;
            ans=(a+(k-1)*d)%mod;
            cout<<ans<<endl;
            continue;
        }
        q=b/a;
        ans=a*quickpow(q,k-1)%mod;
        cout<<ans<<endl;
    }
}