#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using dt = array<int, 2>;

void test() {
  int n;
  cin >> n;

  vector<ll> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n; i++) {
    cin >> b[i];
  }

  ll tot = 0;
  for (int i = n - 2; i >= 0; i--) {
    b[i] = max(b[i], b[i + 1]);
  }

  for (int i = 0; i < n; i++) {
    if (a[i] <= b[i]) {
    	tot += b[i] - a[i];
    }
  }

  cout << tot << "\n";
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int T = 1;  
  cin >> T;
  for (int i = 1; i <= T; i++) {
    test();
  }
  return 0;
}