Submission #297905

#	Time	Username	Problem	Language	Result	Execution time	Memory
297905		Hemimor	Race (IOI11_race)	C++14	0 / 100	1 ms	384 KiB

race

#include "race.h"
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <numeric>
#include <cassert>
#include <vector>
#include <cmath>
#include <queue>
#include <set>
#include <map>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<P,int> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

int res=inf;
ll m;
vi s,vis;
vvp g;
vp c[2];

int Cdfs(int v,int p){
	s[v]=1;
	for(auto i:g[v]){
		int u=i.first;
		if(!vis[u]&&u!=p) s[v]+=Cdfs(u,v);
	}
	return s[v];
}

P Cdfs1(int v,int p,int S){
	P q={inf,0};
	int M=0,S_=S-1;
	for(auto i:g[v]){
		int u=i.first;
		if(!vis[u]&&u!=p){
			q=min(q,Cdfs1(u,v,S));
			M=max(M,s[u]);
			S_-=s[u];
		}
	}
	return min(q,{max(M,S_),v});
}

int Cent(int v){
	Cdfs(v,-1);
	return Cdfs1(v,-1,s[v]).second;
}

void dfs(int v,int par,int t,int len,vp &a){
	if(t<m) a.push_back({t,len});
	if(t==m) res=min(res,(int)len);
	for(auto p:g[v]){
		int u=p.first;
		if(!vis[u]&&u!=par) dfs(u,v,min(inf,p.second+t),len+1,a);
	}
}

void Rec(int v){
	v=Cent(v);
	vis[v]++;
	vvp b;
	int id=0;
	for(auto p:g[v]){
		vp a;
		dfs(p.first,-1,p.second,1,a);
		b.push_back(a);
		for(auto q:a){
			int t=q.first,len=q.first;
			if(c[0][t].second==id){
				if(len<c[0][t].first) c[0][t]={len,id};
			}
			else if(c[1][t].second==id){
				if(len<c[1][t].first) c[1][t]={len,id};
				if(c[0][t].first>c[1][t].first) swap(c[0][t],c[1][t]);
			}
			else if(len<c[0][t].first) c[1][t]=c[0][t],c[0][t]={len,id};
			else if(len<c[1][t].first) c[1][t]={len,id};
		}
		id++;
	}
	for(int i=0;i<(int)b.size();i++){
		for(auto p:b[i]){
			int t=m-p.first;
			if(c[0][t].second!=i) res=min(res,p.second+c[0][t].first);
			if(c[1][t].second!=i) res=min(res,p.second+c[1][t].first);
		}
	}
	for(int i=0;i<(int)b.size();i++) for(auto p:b[i]) c[0][p.first]=c[1][p.first]={inf,inf};
	for(auto p:g[v]) {
		int u=p.first;
		if(!vis[u]) Rec(u);
	}
}

int best_path(int N, int K, int H[][2], int L[]){
	m=K;
	s=vis=vi(N);
	g=vvp(N);
	c[0]=c[1]=vp(m,{inf,inf});
	for(int i=0;i<N-1;i++){
		int u=H[i][0],v=H[i][1];
		g[u].push_back({v,L[i]});
		g[v].push_back({u,L[i]});
	}
	Rec(0);
	if(res==inf) res=-1;
	return res;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57