//NiceDuck
#include "bits/stdc++.h"
typedef long long ll;
using namespace std;
#define FILE "000"
#define foru(i,a,b) for(int i=(int)(a); i<=(int)(b); ++i)
#define ford(i,a,b) for(int i=(int)(a); i>=(int)(b); --i)
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);
#define pb push_back
#define fi first
#define se second
#define pii pair<int,int>
#define pil pair<int,ll>
#define pli pair<ll,int>
#define MOD 1000000007
#define el "\n"


ll calc(int n, int m, ll a[], ll b[])
{
    sort(a+1,a+n+1); sort(b+1,b+m+1);
    if(n==1) return max(abs(a[1]-b[1]),abs(a[1]-b[m]));
    ll ans=0;
    int i=1,j=n,i1=1,j1=m;
    while(i<=j)
    {
        int x=abs(a[i]-b[j1]), y=abs(a[j]-b[i1]);
        if(x>=y)
        {
            ans+=x;
            ++i; --j1;
        }
        else 
        {
            ans+=y;
            --j; ++i1;
        }
    }
    return ans;
}

int main()
{
    fastio
    #ifndef ONLINE_JUDGE
    freopen(FILE ".inp","r",stdin);
    freopen(FILE ".out","w",stdout);
    #endif // ONLINE_JUDGE
    
    int t; cin>>t;
    while(t--)
    {
        int n,m; cin>>n>>m;
        ll a[n+3], b[m+3];
        foru(i,1,n) cin>>a[i];
        foru(i,1,m) cin>>b[i];
        cout<<calc(n,m,a,b)<<el;
    }

    
    return 0;
}