Submission #489265

#	Time	Username	Problem	Language	Result	Execution time	Memory
489265		CSQ31	Inside information (BOI21_servers)	C++17	50 / 100	226 ms	33488 KiB

servers

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define sz(a) (int)(a.size())
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
typedef pair<int,int> pii;
const int MAXN = 2e5;
vector<pii>adj[MAXN];
int dep[MAXN],par[18][MAXN],asc[MAXN],dsc[MAXN],val[MAXN],n,k;
char c[250000];
int a[250000],d[250000];
void dfs(int v,int u,int ww){
	for(int i=1;i<=17;i++)par[i][v] = par[i-1][par[i-1][v]];
	for(pii z:adj[v]){
		int x = z.fi;
		int w = z.se;
		if(x == u)continue;
		val[x] = w;
		asc[x] = dsc[x] = dep[v];
		if(w > ww || v==1)asc[x] = asc[v];	
		if(w < ww || v==1)dsc[x] = dsc[v];
		
		dep[x] = dep[v]+1;
		par[0][x] = v;
		dfs(x,v,w);
	}
}
int jump(int v,int d){
	for(int i=0;i<=17 && d;i++){
		if(d&1)v=par[i][v];
		d/=2;
	}
	return v;
}
int lca(int v,int u){
	if(dep[v] < dep[u])swap(v,u);
	v = jump(v,dep[v] - dep[u]);
	
	if(v==u)return v;
	for(int i=17;i>=0;i--){
		if(par[i][v] != par[i][u]){
			v = par[i][v];
			u = par[i][u];
		}
	}
	return par[0][v];
}
int main()
{
	owo
	cin>>n>>k;
	for(int i=0;i<n+k-1;i++){
		cin>>c[i]>>a[i];
		if(c[i]!='C')cin>>d[i];
		if(c[i] == 'S'){
			adj[a[i]].pb({d[i],i});
			adj[d[i]].pb({a[i],i});
		}
	}
	dfs(1,0,0);
	for(int i=0;i<n+k-1;i++){
		if(c[i]=='C'){
			cout<<42<<'\n';
			continue;
		}
		else if(c[i]=='Q'){ //this solves for Q queries now for C queries
			int v = a[i];
			int u = d[i];

			int m = lca(v,u),last = -1e9;
			if(v!=m)last = val[v];
			else if(u!=m)last = val[jump(u,dep[u]-dep[m]-1)];
			bool ok= (last<=i);
			
			if(asc[v] > dep[m] || dsc[u] > dep[m])ok = 0;
			if(v!=m && u!= m){
				v = jump(v,dep[v]-dep[m]-1);
				u = jump(u,dep[u]-dep[m]-1);
				if(val[u] > val[v])ok = 0;
			}
			if(ok)cout<<"yes"<<'\n';
			else cout<<"no"<<'\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: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5