/*
 *   Copyright (c) 2025 Emon Thakur
 *   All rights reserved.
 */
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int t; cin >> t; while(t--)
    {
        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 = 0;
        long long ans = 0;
        for(int i=n-1;i>=0;i--)
        {
            mx = max(mx , b[i]);
            ans += max(0 , mx-a[i]);
        }
        cout<<ans<<endl;
    }
}