Submission #860288

#	Time	Username	Problem	Language	Result	Execution time	Memory
860288		ReLice	Valley (BOI19_valley)	C++14	0 / 100	106 ms	61060 KiB

valley

#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define sz size()
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define bc back()
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}
const long long inf=1e18+7;
const ll mod=998244353;
const ll N=1e5+7;
const ld eps=1e-9;
vector <vector <pair<ll,ll>> > g(N);
ll pref[N],mn[N];
bool mp[N];
ll p[N][30],up[N][30];
ll d[N],tin[N],tout[N],tiktak;
void calc(ll v){
	for(ll i=2;i<20;i++){
		p[v][i]=p[p[v][i-1]][i-1];
		up[v][i]=min(up[v][i-1],up[p[v][i-1]][i-1]+pref[v]-pref[p[v][i-1]]);
	}
}
void prep(ll v,ll pr){
	if(pr>0)calc(v);
	for(auto i : g[v]){
		if(i.fr==pr) continue;
		p[i.fr][1]=v;
		up[i.fr][1]=min(mn[i.fr],i.sc+mn[v]);
		prep(i.fr,v);
	}
}
void dfs(ll v,ll p){
	mn[v]=inf;
	tin[v]=tiktak++;
	if(mp[v]) mn[v]=0;
	for(auto i : g[v]){
		if(i.fr==p) continue;
		d[i.fr]=d[v]+1;
		pref[i.fr]=pref[v]+i.sc;
		dfs(i.fr,v);
		mn[v]=min(mn[v],mn[i.fr]+i.sc);
		
	}
	tout[v]=tiktak++;
}
void solve(){
    ll i,j,q;
    ll a,b,c=0;
    ll n,r,k;
    cin>>n>>k>>q>>r;
    vector <pair<ll,ll>> edges;
    for(i=1;i<n;i++){
		cin>>a>>b>>c;
		edges.pb({a,b});
		g[a].pb({b,c});
		g[b].pb({a,c});
	}
	for(i=0;i<k;i++){
		cin>>b;
		mp[b]=true;
	}
	for(i=0;i<25;i++){
		for(j=1;j<=n;j++){
			up[j][i]=inf;
		}
	}
	dfs(r,-1);
	prep(r,-1);
	for(j=0;j<q;j++){
		cin>>a>>b;
		if(d[edges[a-1].fr]<d[edges[a-1].sc]){
			a=edges[a-1].sc;
			
		}else{
			a=edges[a-1].fr;
		}
		if(tin[a]>tin[b] || tout[a]<tout[b]){
				cout<<"escaped"<<endl;
			}
			else{
			ll sum=0,ans=inf,v=b;
			for(i=19;i>0;i--){
				if(d[v]-(1ll<<(i-1))>=d[a]){
					ans=min(ans,up[v][i]+sum);
					sum+=pref[v]-pref[p[v][i]];
					v=up[v][i];
					
				}
			}
			if(ans==inf){
				cout<<"oo"<<endl;
			}else{
				cout<<ans<<endl;
			}
		}
	}
}

signed main(){
    start();
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    ll t=1;
    //cin>>t;
    while(t--) solve();
}
/*

 
 
 
*/

Compilation message (stderr)

valley.cpp: In function 'void fre(std::string)':
valley.cpp:24:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:24:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 27
• Subtask 3: 0 / 23
• Subtask 4: 0 / 41