#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

#define pb      push_back
#define debug   cout<<"check"<<endl;cout.flush();
#define all(x)  (x).begin(),(x).end()
#define endl    '\n'

const ll N=200005;
const ll mod=1000000007;
const ll INF=2e18L+5;

void solve(){
    ll n;
    cin>>n;
    vector<ll>v,u;
    
    for(ll i=1;i<=n;i++){
        ll a; cin>>a; v.pb(a);
        
    }
    for(ll i=1;i<=n;i++){
        ll a; cin>>a; u.pb(a);
    }
    ll cnt=0;
    vector<ll>suf(n,0);
    suf[n-1]=u[n-1];
    for(ll i=n-2;i>=0;i--){
        suf[i]=max(u[i],suf[i+1]);
    }
    for(ll i=0;i<n;i++){
        cnt+=max(0LL,suf[i]-v[i]);
    }
    cout<<cnt<<endl;
}

int32_t main(){  
    
    ios::sync_with_stdio(false);cin.tie(nullptr);
    
    int t=1;
    cin>>t;
    for(int i=1;i<=t;i++){
        solve();
    }
    
    return 0;
}