#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"

int get_int(string s) {
    int ans = 0;
    int k = 1;

    for (int i = s.size()-1; i >= 0; i--) {
        int x = s[i] -'0';
        ans += x * k;
        k *= 10;
    }
    return ans;
}

int main() {
    int t; cin >> t; while (t--) {
        int n; cin >> n;
        int a[n + 1];
        int b[n + 1];
        int suf[n + 1] = {0};
        ll ans = 0;
        for (int i = 1; i <= n; i++) {
            cin >> a[i];
        }
        for (int i = 1; i <= n; i++) {
            cin >> b[i];
        }


        suf[n] = b[n];
        for (int i = n - 1; i >= 1; i--) {
            suf[i] = max(b[i], suf[i + 1]);
        }



        for (int i = 1; i <= n; i++) {
            if (a[i] <= suf[i]) {
                ans += suf[i] - a[i];
            }
        }

        cout << ans << endl;
    }

}