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

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
    cin >> T;
    while (T--) {
        int n;
        cin >> n;
        vector<long long> a(n), b(n);

        for (int i = 0; i < n; i++) cin >> a[i];
        for (int i = 0; i < n; i++) cin >> b[i];

        long long profit = 0;
        long long maxSell = 0; 

        
        for (int i = n - 1; i >= 0; i--) {
            maxSell = max(maxSell, b[i]); 
            if (maxSell > a[i]) {
                profit += (maxSell - a[i]); 
            }
        }

        cout << profit << "\n";
    }

    return 0;
}