Submission #1172314

#	Time	Username	Problem	Language	Result	Execution time	Memory
1172314		DanielPr8	Railway (BOI17_railway)	C++20	0 / 100	269 ms	589824 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()

int main(){
    ios_base::sync_with_stdio(0);cin.tie(NULL);
    ll n, m, k, a ,b, s;
    cin >> n >> m >> k;
    vector<set<pll>> g(n);
    vll deg(n);
    for(ll i = 0; i < n-1; ++i){
        cin >> a >> b;
        a--;b--;
        g[a].insert({b,i+1});
        g[b].insert({a,i+1});
        deg[a]++;
        deg[b]++;
    }
    vvl wh(n, vll(m));
    vll am(n);
    for(ll i = 0; i < m; ++i){
        cin >> s;
        while(s--){
            cin >> a;a--;
            am[a]++;
            wh[a][i]=1;
        }
    }
    vll ans;
    queue<ll> pq;
    for(ll i = 0; i < n; ++i)if(deg[i]==1)pq.push(i);
    while(!pq.empty()){
        ll i = pq.front();pq.pop();
        if(g[i].empty())break;
        pll e = *g[i].begin();
        if(am[i]>=k){
            ans.pb(e.s);
            //am[e.f]=n;
        }
        for(ll j = 0; j < m; ++j){
            if(wh[i][j] && !wh[e.f][j]){wh[e.f][j]=1;am[j]++;}
        }
        g[e.f].erase({i, e.s});
        g[i].clear();
        if(g[e.f].size()==1)pq.push(e.f);
    }
    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