Submission #297424

#	Time	Username	Problem	Language	Result	Execution time	Memory
297424		Hemimor	Race (IOI11_race)	C++14	21 / 100	1891 ms	28888 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;

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,ll t,ll len,vpll &a){
	a.push_back({t,len});
	for(auto p:g[v]){
		int u=p.first;
		if(!vis[u]&&u!=par) dfs(u,v,p.second+t,len+1,a);
	}
}

void Rec(int v){
	v=Cent(v);
	vis[v]++;
	vector<vpll> b;
	vl tmp;
	for(auto p:g[v]){
		vpll a;
		dfs(p.first,-1,p.second,1,a);
		b.push_back(a);
		for(auto q:a) tmp.push_back(q.first);
	}
	sort(tmp.begin(),tmp.end());
	tmp.erase(unique(tmp.begin(),tmp.end()),tmp.end());
	map<ll,int> mp;
	int n=(int)tmp.size();
	for(int i=0;i<n;i++) mp[tmp[i]]=i;	
	vector<multiset<ll>> st(n);
	for(int i=0;i<(int)b.size();i++) for(auto p:b[i]) st[mp[p.first]].insert(p.second);
	for(int i=0;i<(int)b.size();i++){
		for(auto p:b[i]) st[mp[p.first]].erase(st[mp[p.first]].find(p.second));
		for(auto p:b[i]) if(mp.find(m-p.first)!=mp.end()){
			int I=mp[m-p.first];
			if(!st[I].empty()) res=min(res,(int)(p.second+*st[I].begin()));
		}
		for(auto p:b[i]) st[mp[p.first]].insert(p.second);
	}
	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);
	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: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57