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

void solve() {
  int n;
  cin >> n;
  vector<int> a(n);
  for (auto& ai : a) {
    cin >> ai;
  }
  vector<int> b(n);
  for (auto& bi : b) {
    cin >> bi;
  }
  vector<int> mx(n + 1);
  for (int i = n - 1; i >= 0; i--) {
    mx[i] = max(mx[i + 1], b[i]);
  }
  int64_t profit = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] < mx[i]) {
      profit = profit + mx[i] - a[i];
    }
  }
  cout << profit << '\n';
}

int main() {
  ios_base::sync_with_stdio(0), cin.tie(0);
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; i++) {
    solve();
  }
  return 0;
}