#include
using namespace std;
int main(){
int t;
cin>>t;
while(t–){
long long n,r;
cin>>n>>r;
long long a[n],b[n],tension=0;
for(long long i=0;i<n;i++){
cin>>a[i];
}
for(long long i=0;i<n;i++){
cin>>b[i];
}
for(long long i=0;i<n;i++){
if(i==0){
tension+=b[i];
}else{
tension+=b[i];
long long diff = (a[i]-a[i-1])*r;
tension = tension -diff;
}
}
cout<<tension<<"\n";
}
}
i am getting correct output but wrong answer in chodechef compilier can anyone help?