Submission #1233557

#	Time	Username	Problem	Language	Result	Execution time	Memory
1233557		chikien2009	Railway (BOI17_railway)	C++20	100 / 100	118 ms	42824 KiB

railway

#include <bits/stdc++.h>

using namespace std;

void setup()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int n, m, k, a, b, sz[100000];
vector<pair<int, int>> g[100000];
vector<int> res, s[100000];

inline map<int, int> DFS(int node, int par, int last)
{
    map<int, int> cur, temp;
    for (auto & i : s[node])
    {
        cur[i]++;
    }    
    for (auto & i : g[node])
    {
        if (i.first != par)
        {
            temp = DFS(i.first, node, i.second);
            if (temp.size() > cur.size())
            {
                swap(cur, temp);
            }
            for (auto & j : temp)
            {
                if (j.second + cur[j.first] == sz[j.first])
                {
                    cur.erase(j.first);
                }
                else
                {
                    cur[j.first] += j.second;
                }
            }
        }
    }
    if (cur.size() >= k)
    {
        res.push_back(last);
    }
    return cur;
}

int main()
{
    setup();

    cin >> n >> m >> k;
    for (int i = 0; i < n - 1; ++i)
    {
        cin >> a >> b;
        g[a - 1].push_back({b - 1, i + 1});
        g[b - 1].push_back({a - 1, i + 1});
    }
    for (int i = 0; i < m; ++i)
    {
        cin >> sz[i];
        for (int j = 0; j < sz[i]; ++j)
        {
            cin >> a;
            s[a - 1].push_back(i);
        }
    }
    DFS(0, 0, 0);
    cout << res.size() << "\n";
    sort(res.begin(), res.end());
    for (auto & i : res)
    {
        cout << i << " ";
    }
    return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25