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

int main() {
    int t;
    cin>>t;
    

    while (t--) {
        int n;  
        cin >> n;

        vector<long long> buyPrices(n);
        vector<long long> sellPrices(n);

        
        for (int i = 0; i < n; i++) {
            cin >> buyPrices[i];
        }

      
        for (int i = 0; i < n; i++) {
            cin >> sellPrices[i];
        }

        vector<long long> maxSellPrice(n);
        maxSellPrice[n - 1] = sellPrices[n - 1];

      
        for (int i = n - 2; i >= 0; i--) {
            if (sellPrices[i] > maxSellPrice[i + 1]) {
                maxSellPrice[i] = sellPrices[i];
            } else {
                maxSellPrice[i] = maxSellPrice[i + 1];
            }
        }

        long long totalProfit = 0;

    
        for (int i = 0; i < n; i++) {
            if (maxSellPrice[i] > buyPrices[i]) {
                totalProfit += maxSellPrice[i] - buyPrices[i];
            }
        }

        cout << totalProfit << "\n";
    }

    return 0;
}