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

int main() {
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        vector<ll> buy(n), sell(n);
        for (int i = 0; i < n; i++) {
            cin >> buy[i];
        }
        for (int i = 0; i < n; i++) {
            cin >> sell[i];
        }
        vector<ll> sufMax(n);
        sufMax[n - 1] = sell[n - 1];
        for (int i = n - 2; i >= 0; i--) {
            sufMax[i] = max(sell[i], sufMax[i + 1]);
        }
        ll profit = 0;
        for (int i = 0; i < n; i++) {
            if (sufMax[i] > buy[i]) {
                profit += (sufMax[i] - buy[i]);
            }
        }

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