Submission #1172390

#	Time	Username	Problem	Language	Result	Execution time	Memory
1172390		DanielPr8	Railway (BOI17_railway)	C++20	0 / 100	1096 ms	17628 KiB

railway

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvl = vector<vll>;
using pll = pair<ll,ll>;
using vpl = vector<pll>;
using vvp = vector<vpl>;
#define f first
#define s second
#define pb push_back
#define all(v) v.begin(),v.end()
vll ed, sz;
vvp g;
void dfs(ll cr, ll pr){
    for(pll i:g[cr]){
        if(i.f!=pr){
            dfs(i.f,cr);
            sz[cr]+=sz[i.f];
            if(sz[i.f]>0){
                ed[i.s]++;
            }
        }
    }
}
int main(){
    ios_base::sync_with_stdio(0);cin.tie(NULL);
    ll n, m, k, a ,b, s;
    cin >> n >> m >> k;
    g = vvp(n);
    for(ll i = 0; i < n-1; ++i){
        cin >> a >> b;
        a--;b--;
        g[a].pb({b,i+1});
        g[b].pb({a,i+1});
    }
    ed = vll(n);
    for(ll i = 0; i < m; ++i){
        sz = vll(n,0);
        cin >> s;
        while(s--){
            cin >> a;a--;
            sz[a]=1;
        }
        dfs(a,a);
    }
    vll ans;
    for(ll i = 0; i < n-1; ++i){
        if(ed[i]>=k)ans.pb(i);
    }
    cout << ans.size() << "\n";
    for(ll i:ans)cout << i << " ";
}

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