Submission #545894

#	Time	Username	Problem	Language	Result	Execution time	Memory
545894		mars4	Railway (BOI17_railway)	C++17	100 / 100	338 ms	75260 KiB

railway

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp> 

using namespace std;
using namespace __gnu_pbds; 

#define ff              first
#define ss              second
#define ll              int64_t
#define ld              long double
#define nl              cout<<"\n"
#define i128            __int128_t
#define all(v)          v.begin(),v.end()
#define mset(a,v)       memset((a),(v),sizeof(a))
#define forn(i,a,b)     for(int64_t i=int64_t(a);i<int64_t(b);++i)
#define forb(i,a,b)     for(int64_t i=int64_t(a);i>=int64_t(b);--i)
#define fastio()        ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);

#define mod         1'000'000'007
#define mod2        998'244'353 
#define inf         1'000'000'000'000'007
#define pi          3.14159265358979323846

template<class key,class cmp=std::less<key>>
using ordered_set=tree<key,null_type,cmp,rb_tree_tag,tree_order_statistics_node_update>;

template<class L,class R> ostream& operator<<(ostream& out,pair<L,R> &p)        {return out<<"("<<p.ff<<", "<<p.ss<<")";}
template<class T> ostream& operator<<(ostream& out,vector<T> &v)                {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,deque<T> &v)                 {out<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())out<<", ";out<<*it;}return out<<"]";}
template<class T> ostream& operator<<(ostream& out,set<T> &s)                   {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class T> ostream& operator<<(ostream& out,ordered_set<T> &s)           {out<<"{";for(auto it=s.begin();it!=s.end();++it){if(it!=s.begin())out<<", ";out<<*it;}return out<<"}";}
template<class L,class R> ostream& operator<<(ostream& out,map<L,R> &m)         {out<<"{";for(auto it=m.begin();it!=m.end();++it){if(it!=m.begin())out<<", ";out<<*it;}return out<<"}";}

void dbg_out() {cerr<<"]\n";}
template<typename Head,typename... Tail> 
void dbg_out(Head H,Tail... T) {cerr<<H;if(sizeof...(Tail))cerr<<", ";dbg_out(T...);}
#ifdef LOCAL
#define dbg(...) cerr<<"["<<#__VA_ARGS__<<"] = [",dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

//---------------------------------mars4---------------------------------

class LCA
{
	ll n;
	ll N;
	ll K;

	void dfs(ll cur,ll prev,vector<vector<ll>> &v)
	{
		ind[cur]=(ll)euler.size();
		euler.push_back(cur);
		euler_depth.push_back(depth[cur]);
		for(ll i:v[cur])
		{
			if(i!=prev)
			{
				depth[i]=depth[cur]+1;
				dfs(i,cur,v);
				euler.push_back(cur);
				euler_depth.push_back(depth[cur]);
			}
		}
	}

	void build()
	{
		N=(ll)euler_depth.size();
		K=64-__builtin_clzll(N);
		st=vector<vector<ll>>(N,vector<ll>(K));
		logN=vector<ll>(N+1);
		for(int i=2;i<=N;i++)
		{
			logN[i]=logN[i/2]+1;
		}
		for(int i=1;i<N;i++)
		{
			st[i][0]=i;
		}
		for(int j=1;j<=K;j++)
		{
			for(int i=0;i+(1ll<<j)<=N;i++)
			{
				if(euler_depth[st[i][j-1]]<euler_depth[st[i+(1ll<<(j-1))][j-1]])
				{
					st[i][j]=st[i][j-1];
				}
				else
				{
					st[i][j]=st[i+(1ll<<(j-1))][j-1];
				}
			}
		}
	}

	public:
	vector<ll> euler;
	vector<ll> ind;
	vector<ll> depth;
	vector<ll> euler_depth;
	vector<vector<ll>> st;
	vector<ll> logN;

	void init(vector<vector<ll>> &v,ll root=0)
	{
		ll n=(ll)v.size();
		ind=vector<ll>(n);
		depth=vector<ll>(n);
		dfs(root,-1,v);
		build();
	}

	ll lca(ll u,ll v)
	{
		if(ind[u]>ind[v])
		{
			swap(u,v);
		}
		ll l=ind[u];
		ll r=ind[v];
		ll j=logN[r-l+1];
		if(euler_depth[st[l][j]]<euler_depth[st[r-(1ll<<j)+1][j]])
		{
			return euler[st[l][j]];
		}
		else
		{
			return euler[st[r-(1ll<<j)+1][j]];
		}
	}
	
	ll dist(ll u,ll v)
	{
		return depth[u]+depth[v]-2*depth[lca(u,v)];
	}
};

class SegtreeSum
{
	ll N;
	vector<ll> segtree;
	vector<ll> lazy;

	ll _build(vector<ll> &a,ll st,ll ed,ll i=1)
	{
		if(st==ed)
			return segtree[i]=a[st];
		ll mid=(st+ed)>>1;
		return segtree[i]=_build(a,st,mid,i<<1)+_build(a,mid+1,ed,i<<1|1);
	}

	void _push(ll st,ll ed,ll val,ll i)
	{
		if(st^ed)
		{
			lazy[i<<1]+=val;
			lazy[i<<1|1]+=val;
		}
	}

	void _update(ll st,ll ed,ll l,ll r,ll val,ll i=1)
	{
		if(lazy[i])
		{
			segtree[i]+=lazy[i]*(ed-st+1);
			_push(st,ed,lazy[i],i);
			lazy[i]=0;
		}
		if(st>ed or st>r or ed<l)
			return;
		if(st>=l and ed<=r)
		{
			segtree[i]+=val*(ed-st+1);
			_push(st,ed,val,i);
			return;
		}
		ll mid=(st+ed)>>1;
		_update(st,mid,l,r,val,i<<1);
		_update(mid+1,ed,l,r,val,i<<1|1);
		segtree[i]=segtree[i<<1]+segtree[i<<1|1];
	}

	ll _query(ll st,ll ed,ll l,ll r,ll i=1)
	{
		if(lazy[i])
		{
			segtree[i]+=lazy[i]*(ed-st+1);
			_push(st,ed,lazy[i],i);
			lazy[i]=0;
		}
		if(st>ed or st>r or ed<l)
			return 0;
		if(st>=l and ed<=r)
			return segtree[i];
		ll mid=(st+ed)>>1;
		return _query(st,mid,l,r,i<<1)+_query(mid+1,ed,l,r,i<<1|1);
	}

	// for prefix sum
	ll _first_element_atleast_x(ll st,ll ed,ll l,ll r,ll val,ll i=1)
	{
		if(lazy[i])
		{
			segtree[i]+=lazy[i]*(ed-st+1);
			_push(st,ed,lazy[i],i);
			lazy[i]=0;
		}
		if(st>ed or st>r or ed<l or segtree[i]<val)
			return -1;
		if(st==ed)
			return st;
		ll mid=(st+ed)>>1;
		ll ind=_first_element_atleast_x(st,mid,l,r,val,i<<1);
		if(ind==-1)
			ind=_first_element_atleast_x(mid+1,ed,l,r,val-segtree[i<<1],i<<1|1);
		return ind;
	}

	public:
	void init(ll n,ll val=0)
	{
		N=n;
		segtree=vector<ll>(N<<2,val);
		lazy=vector<ll>(N<<2);
	}

	void build(vector<ll> &a)
	{
		_build(a,0,N-1);
	}

	void update(ll l,ll r,ll val)
	{
		_update(0,N-1,l,r,val);
	}

	ll query(ll l,ll r)
	{
		return _query(0,N-1,l,r);
	}

	ll first_element_atleast_x(ll l,ll r,ll val)
	{
		return _first_element_atleast_x(0,N-1,l,r,val);
	}

	void clear()
	{
		segtree=vector<ll>(N<<2);
		lazy=vector<ll>(N<<2);
	}
};

class HLD
{
	ll N;
	ll timer;

	void dfs_sz(ll cur,ll prev,vector<vector<ll>> &v)
	{
		child[cur]=1;
		parent[cur]=prev;
		for(ll i:v[cur])
		{
			if(i!=prev)
			{
				depth[i]=depth[cur]+1;
				dfs_sz(i,cur,v);
				child[cur]+=child[i];
			}
		}
	}

	void dfs_hld(ll cur,ll prev,ll top,vector<vector<ll>> &v)
	{
		timer++;
		st[cur]=timer;
		tp[cur]=top;
		dn[top]=cur;
		ll h_ind=-1,h_sz=-1;
		for(ll i=0;i<(ll)v[cur].size();i++)
		{
			if(v[cur][i]!=prev)
			{
				if(child[v[cur][i]]>h_sz)
				{
					h_ind=i;
					h_sz=child[v[cur][i]];
				}
			}
		}
		if(h_ind==-1)
		{
			ed[cur]=timer;
			return;
		}
		swap(v[cur][0],v[cur][h_ind]);
		dfs_hld(v[cur][0],cur,top,v);
		for(ll i:v[cur])
		{
			if(i!=prev and i!=v[cur][0])
			{
				dfs_hld(i,cur,i,v);
			}
		}
		ed[cur]=timer;
	}

	public:
	vector<ll> child;
	vector<ll> parent;
	vector<ll> depth;
	vector<ll> st;
	vector<ll> ed;
	vector<ll> tp;
	vector<ll> dn;

	// use segtree class
	SegtreeSum s;

	void init(vector<vector<ll>> &v,ll root=0)
	{
		N=(ll)v.size();
		s.init(N);
		child=vector<ll>(N);
		parent=vector<ll>(N);
		depth=vector<ll>(N);
		st=vector<ll>(N);
		ed=vector<ll>(N);
		tp=vector<ll>(N);
		dn=vector<ll>(N);
		timer=-1;
		dfs_sz(root,root,v);
		dfs_hld(root,root,root,v);
	}

	void update(ll u,ll v)
	{
		while(tp[u]!=tp[v])
		{
			if(depth[tp[u]]<depth[tp[v]])
				swap(u,v);
			s.update(st[tp[u]],st[u],1);
			u=parent[tp[u]];
		}
		if(depth[u]>depth[v])
			swap(u,v);
		s.update(st[u]+1,st[v],1);
	}

	ll query(ll u,ll v)
	{
		if(depth[u]>depth[v])
		{
			swap(u,v);
		}
		return s.query(st[v],st[v]);
	}
};

vector<vector<ll>> v;

int main()
{
	fastio();
	ll z,n,m,t,k,i,j,l,d,h,r;
	cin>>n>>m>>k;
	v=vector<vector<ll>>(n);
	vector<pair<ll,ll>> e(n-1);
	forn(i,0,n-1)
	{
		cin>>l>>r;
		l--,r--;
		v[l].push_back(r);
		v[r].push_back(l);
		e[i]={l,r};
	}
	LCA lca;
	lca.init(v);
	HLD hld;
	hld.init(v);
	forn(i,0,m)
	{
		cin>>h;
		vector<ll> nodes(h);
		forn(j,0,h)
		{
			cin>>nodes[j];
			nodes[j]--;
		}
		sort(all(nodes),[&](ll a,ll b){
			return hld.st[a]<hld.st[b];
		});
		ll node=-1;
		forn(j,0,h)
		{
			if(j==0)
			{
				node=nodes[j];
			}
			else
			{
				ll ancestor=lca.lca(node,nodes[j]);
				if(ancestor==node)
				{
					hld.update(lca.lca(nodes[j-1],nodes[j]),nodes[j]);
				}
				else
				{
					hld.update(node,nodes[j]);
				}
				node=ancestor;
			}
		}
	}
	vector<ll> ans;
	forn(i,0,n-1)
	{
		if(hld.query(e[i].ff,e[i].ss)>=k)
		{
			ans.push_back(i);
		}
	}
	cout<<(ll)ans.size()<<"\n";
	for(ll i:ans)
	{
		cout<<i+1<<" ";
	}
	nl;
	cerr<<"\nTime elapsed: "<<1000*clock()/CLOCKS_PER_SEC<<"ms\n";
	return 0;
}

Compilation message (stderr)

railway.cpp: In function 'int main()':
railway.cpp:369:5: warning: unused variable 'z' [-Wunused-variable]
  369 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |     ^
railway.cpp:369:11: warning: unused variable 't' [-Wunused-variable]
  369 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |           ^
railway.cpp:369:15: warning: unused variable 'i' [-Wunused-variable]
  369 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |               ^
railway.cpp:369:17: warning: unused variable 'j' [-Wunused-variable]
  369 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |                 ^
railway.cpp:369:21: warning: unused variable 'd' [-Wunused-variable]
  369 |  ll z,n,m,t,k,i,j,l,d,h,r;
      |                     ^

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