#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define pie 2*(acos(0.0))
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define pb push_back
#define endl "\n"
#define lcm(a,b) (a*b)/(__gcd<ll>(a,b))
#define mod 1000000007
#define srt(v) sort(v.begin(),v.end())
#define rsrt(v) sort(v.rbegin(),v.rend())
#define ALLAHU_AKBAR ios::sync_with_stdio(false); cin.tie(nullptr);
//typedef tree<ll, null_type, greater<ll>,rb_tree_tag, tree_order_statistics_node_update> ordered_set;

void sir()
{
    ll n; cin>>n;
    vector<ll>b(n), s(n);
    for(auto &e:b) cin>>e;
    for(auto &e:s)cin>>e;

    ll ans =0;
    ll mx = -1;
    for(ll i=n-1; i>=0; i--)
    {
        mx = max(s[i], mx);

        if(mx>b[i]) ans += (mx-b[i]);

    }
    //cout<<mx<<endl;
    cout<<ans<<endl;

}

int main() {
    ALLAHU_AKBAR

    ll t = 1;
    cin>>t;
    while(t--)
    {
        sir();
    }
    return 0;
}