제출 #865854

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
865854		AbdelmagedNour	Inside information (BOI21_servers)	C++17	100 / 100	2920 ms	54636 KiB

servers

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
using namespace std;
typedef long long ll;
const int N=250005,SQ=500;
vector<vector<pair<int,int>>>adj(N);
vector<int>cur_adj[N],order;
int in[N],out[N],dep[N],p[N][18],val[N],max_inc[N],max_dec[N],T;
void init_dfs(int v,int par){
	in[v]=++T;order.push_back(v);
	p[v][0]=par;
	for(int i=1;i<18;i++)p[v][i]=p[p[v][i-1]][i-1];
	max_inc[v]=max_dec[v]=par;
	if(val[v]<val[par])max_inc[v]=max_inc[par];
	else max_dec[v]=max_dec[par];
	for(auto&e:adj[v]){
		int u=e.first,w=e.second;
		if(u==par)continue;
		dep[u]=dep[v]+1;
		val[u]=w;
		init_dfs(u,v);
	}
	out[v]=T;
}
bool anc(int v,int u){
	return in[v]<=in[u]&&out[u]<=out[v];
}
int max_in_path(int u,int v){
	if(anc(u,v))return val[v];
	int pu=u,pv=v;
	for(int i=17;i>=0;i--){
		if(!anc(p[pu][i],v))pu=p[pu][i];
		if(!anc(p[pv][i],u))pv=p[pv][i];
	}
	if(p[pu][0]==v)return val[pu];
	return val[pu]<val[pv]?val[v]:INT_MAX;
}
bool can_reach(int u,int v,int Time){
	if(u==v)return 1;
	if((!anc(max_inc[u],v))||(!anc(max_dec[v],u)))return 0;
	if(!anc(v,u)&&val[v]>Time)return 0;
	return max_in_path(u,v)<=Time;
}
int dp_down[N],dp_up[N],dp[N],vis[N];
void dfs_down(int v,int par){
	if(vis[v])return;
	vis[v]=1;
	dp_down[v]=dp[v]=1;
	for(auto&u:cur_adj[v]){
		if(u==par)continue;
		dfs_down(u,v);
		if(val[u]>val[v])dp_down[v]+=dp_down[u];
		dp[v]+=dp_down[u];
	}
}
void dfs_up(int v,int par,int sum=0){
	dp_up[v]=sum+(par!=v);
	if(val[par]>val[v])dp_up[v]+=dp_up[par];
	dp[v]+=dp_up[v];
	sum=0;
	for(int i=cur_adj[v].size()-1;i>=0;i--){
		int u=cur_adj[v][i];
		if(u==par)continue;
		dfs_up(u,v,sum);
		sum+=dp_down[u];
	}
}
void reclac(){
	memset(vis+1,0,int(order.size())*sizeof(vis[1]));
	for(auto&u:order){
		if(vis[u])continue;
		dfs_down(u,u);
		dfs_up(u,u);
	}
}
char op[N];
int A[N],B[N];
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,q;
	cin>>n>>q;
	for(int i=1;i<n+q;i++){
		cin>>op[i];
		if(op[i]=='S'){
			cin>>A[i]>>B[i];
			adj[A[i]].push_back({B[i],i});
			adj[B[i]].push_back({A[i],i});
		}
		if(op[i]=='Q')cin>>A[i]>>B[i];
		if(op[i]=='C')cin>>A[i];
	}
	init_dfs(1,1);
	fill(dp+1,dp+n+1,1);
	int cnt=0;
	vector<int>edges;
	for(int i=1;i<n+q;i++){
		if(cnt==SQ)reclac(),cnt=0,edges.clear();
		if(op[i]=='S'){
			edges.push_back(i);
			cur_adj[A[i]].push_back(B[i]);
			cur_adj[B[i]].push_back(A[i]);
			cnt++;
		}else if(op[i]=='Q')cout<<(can_reach(B[i],A[i],i)?"yes\n":"no\n");
		else{
			int res=dp[A[i]];
			for(auto&e:edges){
				int u=A[e],v=B[e];
				if(val[u]!=e)swap(u,v);
				if(!anc(u,A[i])&&can_reach(A[i],u,i))res++;
				else if(anc(u,A[i])&&can_reach(A[i],v,i))res++;
			}
			cout<<res<<"\n";
		}
	}
	return 0;
}

• Subtask 1: 2.5 / 2.5
• Subtask 2: 2.5 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 2.5 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 5 / 5
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 12.5 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 17.5 / 17.5