7-9 鱼与熊掌

输入样例：

4 8
3 4 1 8
4 7 1 8 4
5 6 5 1 2 3
4 3 2 4 8
3
2 3
7 6
8 4

输出样例：

2
0
3

第一种动态数组vector

#include <bits/stdc++.h>
using namespace std;
typedef long int ll;
const int N = 1e6 + 10;
void solve()
{
    int n, m, k;
    cin >> n >> m;
    vector<vector<int>> aa(n);
    for (int i = 0; i < n; i++)
    {
        int x;
        cin >> x;
        for (int j = 0; j < x; j++)
        {
            int op;
            cin >> op;
            aa[i].push_back(op);
        }
    }
    int x1;
    cin >> x1;
    int cnt = 0;
    while (x1--)
    {
        int a, b;
        cin >> a >> b;
        int cnt = 0;
        for (int i = 0; i < n; i++)
        {
            bool f1 = false, f2 = false;
            for (vector<int>::iterator it = aa[i].begin(); it != aa[i].end(); it++)
            {
                if (*it == a)
                    f1 = true;
                if (*it == b)
                    f2 = true;
            }
            if (f1 && f2)
                cnt++;
        }
        cout << cnt << endl;
    }
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    while (t--)
    {
        solve();
    }
    return 0;
}

第二种unordered_map

#include <iostream>
#include <unordered_map>
#include <vector>
using namespace std;
typedef long int ll;
const int N = 1e5 + 100;
unordered_map<int, int> a[N];
void solve()
{
    int n, m, k;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        cin >> k;
        for (int j = 0; j < k; j++)
        {
            int x;
            cin >> x;
            a[i][x] = 1;
        }
    }
    int q;
    cin >> q;
    for (int j = 0; j < q; j++)
    {
        int x, y;
        cin >> x >> y;
        int cnt = 0;
        for (int i = 1; i <= n; i++)
            if (a[i].count(x) && a[i].count(y))
                cnt++;
        cout << cnt << endl;
    }
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t=1;
    while (t--)
    {
        solve();
    }
    return 0;
}