/* Problem URL: https://codeforces.com/problemset/problem/1941/F */

#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;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;


void pre()
{

}

#define TEST 1

void solve()
{
    int n, m, k;
    cin >> n >> m >> k;

    vl a(n);
    vl d(m);
    vl f(k);
    cin >> a >> d >> f;

    map<ll, int, greater<>> c;
    rep(i, n - 1) {
        c[a[i + 1] - a[i]]++;
    }

    if (c.begin()->second > 1 || c.begin()->first == 1) {
        cout << c.begin()->first << '\n';
        return;
    }

    sortv(d);
    sortv(f);

    ll lim = c.begin()->first;

    int choice = 0;
    rep(i, n - 1) {
        if (a[i + 1] - a[i] == lim) {
            choice = i;
            break;
        }
    }

    auto getlesseq = [&](ll mid) {
        ll ans = -1;
        rep(i, m) {
            auto itr = upper_bound(all(f), mid - d[i]) - f.begin();
            if (itr == 0) {
                continue;
            }

            rmax(ans, d[i] + f[itr - 1]);
        }

        return ans;
    };

    auto getgreatereq = [&](ll mid) {
        ll ans = OO;
        rep(i, m) {
            auto itr = lower_bound(all(f), mid - d[i]) - f.begin();
            if (itr == k) {
                continue;
            }

            rmin(ans, d[i] + f[itr]);
        }

        return ans;
    };

    ll ch = a[choice];
    ll bt = max(ch - a[choice], a[choice + 1] - ch);

    auto getans = [&](ll m) {
        if (m < a[choice] || m > a[choice + 1]) {
            return;
        }
        ll tbt = max(m - a[choice], a[choice + 1] - m);

        if (tbt < bt) {
            bt = tbt;
            ch = m;
        }
    };

    ll mid = (a[choice] + a[choice + 1]) >> 1;

    getans(getlesseq(mid));
    getans(getgreatereq(mid));

    a.push_back(ch);
    sortv(a);

    ll ans = 0;
    rep(i, n) {
        rmax(ans, a[i + 1] - a[i]);
    }

    cout << ans << '\n';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    pre();

    int t;
    (TEST && cin >> t) || (t = 1);
    while (t--) {
        solve();
    }
}