Submission #747417

#	Time	Username	Problem	Language	Result	Execution time	Memory
747417		vjudge1	Railway (BOI17_railway)	C++17	23 / 100	472 ms	1748 KiB

railway

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 10001;
int n, m, k, x;
vector<pair<int, int>> g[MAXN];
set<int> v;
int cnt[MAXN];

int dfs(int u, int p) {
    int s = 0;
    s += v.find(u) != v.end();
    for (auto [v, idx] : g[u]) {
        if (v != p) {
            int f = dfs(v, u);
            if (f > 0 && f < x) cnt[idx]++;
            s += f;
        }
    }
    return s;
}

int main()
{
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n >> m >> k;
    for (int i = 1; i <= n - 1; i++) {
        int a, b; cin >> a >> b;
        g[a].push_back({b,i});
        g[b].push_back({a,i});
    }
    for (int i = 1; i <= m; i++) {
        cin >> x;
        v.clear();
        for (int j = 0; j < x; j++) {
            int f; cin >> f;
            v.insert(f);
        }
        dfs(1, 0);
    }
    vector<int> ans;
    for (int i = 1; i <= n; i++) {
        if (cnt[i] >= k) ans.push_back(i);
    }
    cout << ans.size() << "\n";
    for (int i : ans) cout << i << " ";
    cout << "\n";
    return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 0 / 7
• Subtask 4: 0 / 29
• Subtask 5: 0 / 16
• Subtask 6: 0 / 25