#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pii pair<int,int>
#define Fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
const int MOD = 1000000007;
const int INF = 1e18;
const int N = 2e5;
void solve(int tc){
    int n; cin >> n;
    vector<int>a(n),b(n);
    for(int i=0;i<n;i++)cin >> a[i];
    for(int i=0;i<n;i++)cin >> b[i];
    int mx = -INF,ans = 0;
    for(int i=n-1;i>=0;i--){
        mx = max(mx,b[i]);
        ans += max(0ll,mx - a[i]);
    }
    cout << ans << endl;
}
int32_t main(){
    Fast
    int t=1;
    cin >> t;
    for(int tc=1;tc<=t;tc++)
        solve(tc);
    return 0;
}