#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<string>#include<cmath>using namespace std;long long dp[500005],sum[500005],a[500005];long long G(long long x,long long y){return dp[y]+sum[x]+y*a[y+1]-sum[y]-dp[x]-x*a[x+1];}long long S(long long x,long long y){return a[y+1]-a[x+1];}long long q[500005];int r,f;void insert(int k,int t){q[++r]=k;for(long long i=r-1;i>f+1;i--){long long x=q[i-1],y=q[i],z=q[i+1];if(!(G(x,y)*S(y,z)<G(y,z)*S(x,y)))q[i]=q[r--];elsebreak;}}void init(){r=f=0;memset(q,0,sizeof(q));memset(dp,0,sizeof(dp));}int main(){int c,n,m;scanf("%d",&c);while(c--){scanf("%d%d",&n,&m);sum[0]=0;init();for(int i=1;i<=n;i++){scanf("%lld",&a[i]);sum[i]=sum[i-1]+a[i];}for(long long i=1;i<=n;i++){while(f+1<r&&G(q[f+1],q[f+2])<=i*S(q[f+1],q[f+2]))f++;long long tem=f<r?q[f+1]:0;dp[i]=dp[tem]+sum[i]-sum[tem]-(i-tem)*a[tem+1];if(i>=2*m-1){insert(i-m+1,i+1);}}printf("%lldn",dp[n]);}return 0;}
