https://pintia.cn/problem-sets/994805046380707840/exam/problems/994805070149828608?type=7&page=1

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define rep(i,a,n) for (int i=a;i<=n;i++)
#define per(i,a,n) for (int i=a;i>=n;i--)
#define oz 998244353
#define N 200010
#define INF 0x3f3f3f3f
typedef long long ll;
const int mod = 1e9 + 7;


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

    vector<set<int>> s(n + 1);

    for (int i = 1; i <= n; i++) {

        set<int> st;
        int m;
        cin >> m;

        while (m --) {
            int x;
            cin >> x;
            st.insert(x);
        }

        s[i] = st;
    }

    int m;
    cin >> m;

    while (m --) {
        int l, r;
        cin >> l >> r;
        int cnt = 0;

        for (auto t : s[l]) {
            if (s[r].find(t) != s[r].end())cnt ++;
        }

        double res = cnt * 100.0 / (s[l].size() + s[r].size() - cnt);

        cout << fixed << setprecision(2);
        cout << res;
        cout << "%" << endl;
    }
}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T = 1;
//  cin >> T;
    while (T --)

        solve();

    return 0;
}