//Now_Or_Never
/****Author: OrionJaman**/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define int long long
const int N = 1e5 + 10;
const int mod = 1e9+7;
typedef long double ld;
typedef unsigned long long ull;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
#define L(i, j, k)                            for (int i = (j); i < (k); i++)
#define R(i, j, k)                            for (int i = (j); i >= (k); i--)
#define yes                                   cout << "YES"<< nl;
#define no                                    cout << "NO" << nl;
#define nl                                    "\n"
#define rtn                                   return 0
#define bk                                    break
#define ct                                    continue
#define mp                                    make_pair
#define index_of(x) order_of_key(x)
#define value_index(x) find_by_order(x)
#define countsetbit(x)                        __builtin_popcountll(x);
#define countldzro(x)                         __builtin_clz(x); 
#define countrlzro(x)                         __builtin_ctz(x); 
#define ve(a)                                 vector<a>
#define se(a)                                 set<a>
#define pa(a, b)                              pair<a, b>
#define ma(a, b)                              map<a, b>
#define qu(a)                                 queue<a>
#define st(a)                                 stack<a>
#define all(a)                                v.begin(), v.end()
#define pp                                    pop_back()
#define pb                                    push_back
#define in(v)                                 for (auto &vl : v){ cin >> vl;}
#define pvt(al)                               for (auto &a : al) cout << a << " "; cout << nl;
#define pmt(al)                               for (auto &a : al) cout << a.first << " "<< a.second <<nl; cout << nl;
#define fastcio();                            ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
int inv(int i) {if (i == 1) return 1; return (mod - ((mod / i) * inv(mod % i)) % mod) % mod;}
int mod_mul(int a, int b) {a = a % mod; b = b % mod; return (((a * b) % mod) + mod) % mod;}
int mod_add(int a, int b) {a = a % mod; b = b % mod; return (((a + b) % mod) + mod) % mod;}
int mod_sub(int a, int b) {a = a % mod; b = b % mod; return (((a - b + mod) % mod) + mod) % mod;}
int ceil_div(int a, int b) {return a % b == 0 ? a / b : a / b + 1;}
int lcm(int a, int b){ if(a*b==0) return 0; else return a*b/__gcd(a,b);}
int binexp(int a,int b){ int ans=1; a=a%mod; while(b){if(b&1){ans=(ans*a)%mod;}a=(a*a)%mod;b>>=1;}return ans;}
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
void ori()
{
    int n;cin>>n;
    vector<int>f1(n),f2(n);
    in(f1) in(f2)
    for(int i=n-2;i>=0;i--){
       f2[i]=max(f2[i],f2[i+1]);
    }
    int lv=0;
    L(i,0,n){
        if(f1[i]<f2[i])lv+=abs(f1[i]-f2[i]);
    }
    cout<<lv<<nl;
}
int32_t main()
{
    fastcio();
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    int t;
    cin >> t;
    while (t--)
        ori();
    return 0;
}