Submission #581960

#	Time	Username	Problem	Language	Result	Execution time	Memory
581960		WongChun1234	Inside information (BOI21_servers)	C++14	20 / 100	3571 ms	373928 KiB

servers

#include<bits/stdc++.h>
using namespace std;
const int N=120050;
const int Q=240050;
const bool DEBUG=0;
int n,k,sz[N],u[Q],v[Q];
char ty[Q];
bool del[N];
map<pair<int,int>,int> t;
map<int,int> tonde[N],frmnde[N],incen[N];
vector<int> adj[N];
void prec(int nde,int par){
	sz[nde]=1;
	for (int i:adj[nde]){
		if (del[i]) continue;
		if (i==par) continue;
		prec(i,nde);
		sz[nde]+=sz[i];
	}
}
int findcen(int nde,int par,int mx){
	for (int i:adj[nde]){
		if (del[i]) continue;
		if (i==par) continue;
		if (sz[i]>=mx/2) return findcen(i,nde,mx);
	}
	return nde;
}
void comp(int nde,int par,int smallrt,int bigrt,int mindist,int mxdist){
	if (DEBUG) cerr<<nde<<":"<<par<<" "<<smallrt<<","<<bigrt<<"::"<<mindist<<","<<mxdist<<"\n";
	incen[nde][bigrt]=smallrt;
	tonde[bigrt][nde]=mxdist;
	frmnde[bigrt][nde]=mindist;
	for (int i:adj[nde]){
		if (del[i]) continue;
		if (i==par) continue;
		if (t[{nde,i}]>mxdist){
			comp(i,nde,smallrt,bigrt,INT_MIN,t[{nde,i}]);
		}else if (t[{nde,i}]<mindist){
			comp(i,nde,smallrt,bigrt,t[{nde,i}],INT_MAX);
		}else{
			comp(i,nde,smallrt,bigrt,INT_MIN,INT_MAX);
		}
	}
}
void dc(int nde){
	prec(nde,nde);
	int cen=findcen(nde,nde,sz[nde]);
	if (DEBUG) cerr<<nde<<":"<<cen<<"uwuuwu\n";
	del[cen]=1;
	for (int i:adj[cen]){
		if (del[i]) continue;
		comp(i,cen,i,cen,t[{cen,i}],t[{cen,i}]);
	}
	for (int i:adj[cen]){
		if (del[i]) continue;
		dc(i);
	}
}
bool check(int rt,int v,int u,int id){
	// v->u
	if (u==rt){
		if (frmnde[rt][v]==INT_MIN) return 0;
		return (t[{rt,incen[v][rt]}]<=id);
	}else if (v==rt){
		if (tonde[rt][u]==INT_MAX) return 0;
		return (tonde[rt][u]<=id);
	}else{
		if (incen[u][rt]==incen[v][rt]) return 0;
		if (t[{incen[v][rt],rt}]>t[{incen[u][rt],rt}]) return 0;
		if (frmnde[rt][v]==INT_MIN) return 0;
		if (tonde[rt][u]>id) return 0;
		return 1;
	}
}
int main(){
	cin>>n>>k;
	for (int i=1;i<n+k;i++){
		cin>>ty[i]>>u[i];
		if (ty[i]=='S'){
			cin>>v[i];
			adj[u[i]].push_back(v[i]);
			adj[v[i]].push_back(u[i]);
			t[{u[i],v[i]}]=i;
			t[{v[i],u[i]}]=i;
		}else if (ty[i]=='Q'){
			cin>>v[i];
		}else{
			//???
		}
	}
	dc(1);
	for (int i=1;i<n+k;i++){
		if (ty[i]=='Q'){
			//check if v->u exists
			if (u[i]==v[i]){
				cout<<"yes\n";
				goto skip;
			}
			if (DEBUG) cerr<<v[i]<<",,"<<u[i]<<"\n";
			for (auto j:incen[v[i]]){
				if (!j.second) continue;
				if (DEBUG) cerr<<j.first<<"::"<<j.second<<"a\n";
				if ((!!incen[u[i]][j.first])||j.first==u[i]){
					if (DEBUG) cerr<<v[i]<<"->"<<incen[v[i]][j.first]<<"--"<<j.first<<"--"<<incen[u[i]][j.first]<<"->"<<u[i]<<"\n";
					if (check(j.first,v[i],u[i],i)){
						cout<<"yes\n";
						goto skip;
					}
				}
			}
			if (incen[u[i]][v[i]]){
				if (check(v[i],v[i],u[i],i)){
					cout<<"yes\n";
					goto skip;
				}
			}
			cout<<"no\n";
			skip:;
		}else if (ty[i]=='C'){
			cout<<"42\n";
		}
	}
}

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 5
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 0 / 17.5
• Subtask 12: 0 / 17.5