Submission #244642

#	Time	Username	Problem	Language	Result	Execution time	Memory
244642		santaclaus03	Railway (BOI17_railway)	C++14	23 / 100	1096 ms	11000 KiB

railway

#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using ii = pair<int, int>;
using vb = vector<bool>;
using vvi = vector<vi>;
using vii = vector<ii>;

vector<vii> tree;
vi req;
vb connect;

bool dfs(int u, int p) {
    bool ans = connect[u];
    for (ii & e : tree[u]) {
        if (e.second != p && dfs(e.second, u)) {
            ans = true;
            req[e.first]++;
        }
    }
    return ans;
}

int main() {
    int n, m, k; cin >> n >> m >> k;
    tree.resize(n), req.resize(n - 1);
    for (int i = 0; i < n - 1; ++i) {
        int a, b; cin >> a >> b; a--; b--;
        tree[a].emplace_back(i, b);
        tree[b].emplace_back(i, a);
    }
    for (int i = 0; i < m; ++i) {
        int s; cin >> s;
        connect.assign(n, 0);
        int c;
        for (int j = 0; j < s; ++j) {
            cin >> c; c--;
            connect[c] = 1;
        }
        dfs(c, -1);
    }
    vi ans;
    for (int i = 0; i < n - 1; ++i) {
        if (req[i] >= k) ans.push_back(i + 1);
    }
    cout << ans.size() << endl;
    for (int e : ans) cout << e << " ";
    cout << endl;
    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