Submission #1095674

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095674		vjudge1	Railway (BOI17_railway)	C++17	100 / 100	79 ms	39888 KiB

railway

#include<bits/stdc++.h>
using namespace std;
#define task "test"
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define bit(n,i) ((n>>i)&1)
#define all(x) x.begin(),x.end()
//#pragma GCC optimize("O2,unroll-loops")
//#pragma GCC target("avx,avx2,bmi,bmi2,sse,sse2,sse3,ssse3,sse4,popcnt")
#define int long long
typedef long long ll;
typedef pair<int,int> pii;
typedef double ld;
typedef pair<ld,ld> pdd;
typedef pair<ll,ll> pll;
const ll maxn=1e5+2;
const ll inf=1e18;
const ll mod=1e9+7;
const ll base=311;
int n,m,k,ans;
vector<int> adj[maxn],res;
int in[maxn],out[maxn],Time,par[maxn][20],sum[maxn];
void dfs(int u,int pre)
{
    in[u]=++Time;
    par[u][0]=pre;
    for (int i=1;i<=17;i++)
    {
        par[u][i]=par[par[u][i-1]][i-1];
    }
    for (int v: adj[u])
    {
        if (v==pre) continue;
        dfs(v,u);
    }
    out[u]=Time;
}
inline bool is_ancestor(int u,int v)
{
    return (in[u]<=in[v] && out[v]<=out[u]);
}
int lca(int u,int v)
{
    if (is_ancestor(u,v)) return u;
    if (is_ancestor(v,u)) return v;
    for (int i=17;i>=0;i--)
    {
        if (!is_ancestor(par[u][i],v)) u=par[u][i];
    }
    return par[u][0];
}
int d[maxn],kkk[maxn];
void dfs1(int u,int pre)
{
    for (int v:adj[u])
    {
        if (v==pre) continue;
        dfs1(v, u);
        sum[u]+=sum[v];
    }
    if (sum[u]>=k)
    {
        ans++;
        res.pb(kkk[u]);
    }
    //cout <<"ww "<< u<< ' '<<sum[u]<<'\n';

}
vector<int> a[maxn];
pii ed[maxn];
void sol()
{
    cin >> n>> m>> k;
    for (int i=1;i<n;i++)
    {
        int u,v;cin >> u>>v;
        adj[u].pb(v);
        adj[v].pb(u);
        ed[i]={u,v};
    }
    dfs(1,1);
    for (int i=1;i<n;i++)
    {
        if (is_ancestor(ed[i].fi,ed[i].se))
        {
            kkk[ed[i].se]=i;
        }
        else kkk[ed[i].fi]=i;
    }
    for (int i=1;i<=m;i++)
    {
        cin >> d[i];
        for (int j=1;j<=d[i];j++)
        {
            int x;cin >> x;
            a[i].pb(x);
            sum[x]++;
        }
        sort(all(a[i]),[](int u,int v){
            return in[u]< in[v];
             });
        int hi=a[i][d[i]-1];
        for (int j=0;j<d[i]-1;j++)
        {
            hi=lca(hi,a[i][j]);
            sum[lca(a[i][j],a[i][j+1])]--;
        }
        sum[hi]--;
    }
    dfs1(1,1);
    cout << ans<<'\n';
    sort(all(res));
    for (int v: res) cout << v<<' ';

}
int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    if (fopen(task".inp","r"))
    {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
//    int theta; cin >> theta;
    int t=1;//cin >> t;
    while (t--) sol();
}

Compilation message (stderr)

railway.cpp: In function 'int32_t main()':
railway.cpp:128:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
railway.cpp:129:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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