#include<bits/stdc++.h>
using namespace std;
const int N=3e5+10;
typedef long long ll;
int T,n,k,x[N],a[N],p[N];
ll f[N][60],ans;
void getmin(ll &a,ll b){if(a>b)a=b;}
void work(int u,int v,int w,int m)
{
	for(int i=0;i<=k;i++) f[u][i]=f[v][i]+1ll*a[v]*abs(x[u]-x[v]);
	for(int i=1;i<=k;i++) getmin(f[u][i],f[w][i-1]+1ll*a[w]*abs(x[w]-x[u]));
	for(int i=0;i<=m;i++) getmin(ans,f[u][i]+1ll*a[u]*abs(x[u]-x[n]));
}
vector<int> v1,v2;
int main()
{
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d%d",&n,&k);
		k=min(50,k);
		for(int i=1;i<=n;i++) scanf("%d",&x[i]),p[i]=i;
		for(int i=1;i<=n;i++) scanf("%d",&a[i]);
		if(n==1) {puts("0");continue;}
		sort(p+1,p+n+1,[](int a,int b){return x[a]<x[b];});
		int w=0;
		for(int i=1;i<=n;i++) if(p[i]==1) w=i;
		v1.clear(),v2.clear();
		v1.push_back(1),v2.push_back(1);
		for(int i=w+1;i<=n;i++)
			if(a[v1.back()]>a[p[i]]) v1.push_back(p[i]);
		for(int i=w-1;i;i--)
			if(a[v2.back()]>a[p[i]]) v2.push_back(p[i]);
		ans=1ll*a[1]*abs(x[1]-x[n]);
		for(int i=0;i<=k;i++) f[1][0]=0;
		int p1=(x[n]>x[1]);
		for(int i=0,j=0,n1=v1.size(),n2=v2.size();!(i==n1-1&&j==n2-1);)
		{
			if(i==n1-1||(j<n2-1&&a[v2[j+1]]<a[v1[i+1]])) work(v2[j+1],v2[j],v1[i],k-p1),j++;
			else work(v1[i+1],v1[i],v2[j],k-(p1^1)),i++;
		}
		printf("%lld\n",ans);
	}
}