#include<bits/stdc++.h>
using namespace std;
int main()
{
int t,j;
cin>>t;
for(j=0;j<t;j++)
{
int N,P;
cin>>N>>P;
int A[N],i,tot=0;
for(i=0;i<N;++i)
{
cin>>A[i];
}
//sort(A,A+N);
for(i=0;i<P;++i)
{
tot+=A[P-1]-A[i];
}
int tot1=0;
for(i=P;i<N;++i)
{
tot1=tot+(P-1)*(A[i]-A[i-1]);
tot1-=(A[i-1]-A[i-(P)]);
if(tot1<tot&&tot1>=0)
{
tot=tot1;
}
}
cout<<"Case #"<<j+1<<": "<<tot<<endl;
}
}
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