#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
using LL=long long;
const int N=300005;
int T,n,K,x[N],s[N],id[N],id_[N];
struct node{
	LL x;
	int k;
	node operator+(const node&rhs)const{return (node){x+rhs.x,k+rhs.k};}
	bool operator<(const node&rhs)const{
		return tie(x,k)<tie(rhs.x,rhs.k);
	}
};
node dp[N][2];
node DP(LL mid,int op){
	
	rep(i,1,n){
		dp[i][0]=dp[i][1]=(node){LL(1e18),0};
	}
	int p1=id_[1];
	dp[p1][0]=(node){0,0};
	dp[p1][1]=(node){0,0};
	
	int l=p1-1,r=p1+1;
	
	auto up=[&](int u,int v){
		int o1=u<v?1:0;
		rep(o2,0,1){
			dp[v][o1]=min(dp[v][o1],(node){dp[u][o2].x+1LL*abs(x[u]-x[v])*s[u]+(o1!=o2?mid:0),dp[u][o2].k+(o1!=o2?1:0)});
		}
	};
	if(l>=1)up(p1,l);
	if(r<=n)up(p1,r);
	
	while(l>1||r<n){
		if(l==1||(r<n&&s[l]<=s[r])){
			up(r,l);
			if(r<n){
				up(r,r+1);
				++r;
			}
		}else{
			up(l,r);
			if(l>1){
				up(l,l-1);
				--l;
			}
		}
	}
	up(1,n),up(n,1);
	rep(i,1,n)up(i,id_[n]);
	return dp[id_[n]][op];
}
signed main(){
#ifdef xay5421
	freopen("a.in","r",stdin);
#endif
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin>>T;
	while(T--){
		cin>>n>>K;
		rep(i,1,n){
			cin>>x[i];
		}
		rep(i,1,n){
			cin>>s[i];
		}
		rep(i,1,n)id[i]=i;
		sort(id+1,id+n+1,[&](int lhs,int rhs){return x[lhs]<x[rhs];});
		rep(i,1,n)id_[id[i]]=i;
		{
			static int tmp[N];
			rep(i,1,n)tmp[i]=x[i];
			rep(i,1,n)x[id[i]]=tmp[i];
			rep(i,1,n)tmp[i]=s[i];
			rep(i,1,n)s[id[i]]=tmp[i];
		}
		per(i,id_[1]-1,1){
			s[i]=min(s[i],s[i+1]);
		}
		rep(i,id_[1]+1,n){
			s[i]=min(s[i],s[i-1]);
		}
		LL ans=9e18;
		rep(op,0,1){
			LL l=0,r=LL(1e18)+5,res=0;
			while(l<=r){
				// cerr<<l<<' '<<r<<'\n';
				LL mid=(l+r)>>1;
				auto ret=DP(mid,op);
				if(ret.k<=K)r=mid-1,res=mid;
				else l=mid+1;
			}
			auto ret=DP(res,op);
			ans=min(ans,ret.x-1LL*K*res);
		}
		printf("%lld\n",ans);
	}
	return 0;
}