Submission #638067

#	Time	Username	Problem	Language	Result	Execution time	Memory
638067		ojoConmigo	Railway (BOI17_railway)	C++17	23 / 100	1082 ms	15140 KiB

railway

#include <bits/stdc++.h>
using namespace std;

vector<vector<pair<int,int>>> g;
vector<int> ask;

bool dfs(int nodo, int p, set<int> & vecindarios){
    bool b = false;
    if(vecindarios.find(nodo) != vecindarios.end()){
        b = true;
        vecindarios.erase(nodo);
        if(vecindarios.empty()) return true;
    }
    for(auto pareja : g[nodo]){
        int v = pareja.first;
        if(v == p)continue;
        int ind = pareja.second;
        if(dfs(v,nodo,vecindarios)){
            b = true;
            ask[ind]++;
        }
    }
    return b;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n,m,k;
    cin >> n >> m >> k;
    //vector<pair<int,int>> tracks(n-1);
    g.resize(n);
    for(int i=0; i<n-1; i++){
        int a,b;
        cin >> a >> b;
        a--;b--;
        //tracks[i] = {a,b};
        g[a].emplace_back(b,i);
        g[b].emplace_back(a,i);
    }
    
    ask.assign(n-1,0);
    for(int i=0; i<m; i++){
        int len;
        cin >> len;
        set<int> vecindarios;
        int x;
        for(int j=0; j<len; j++){
            cin >> x;
            x--;
            vecindarios.insert(x);
        }
        //dfs
        vecindarios.erase(x);
        dfs(x,-1,vecindarios);
    }
    
    vector<int> ans;
    for(int i=0; i<n-1; i++){
        if(ask[i] < k)continue;
        ans.push_back(i);
    }
    cout << ans.size() << endl;
    for(int x : ans){
        cout << x+1 << " ";
    }
    cout << endl;
}

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