Submission #286815

#	Time	Username	Problem	Language	Result	Execution time	Memory
286815		TMJN	Dreaming (IOI13_dreaming)	C++17	100 / 100	115 ms	16604 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;

struct edge{
	int to,dist;
};

bool vis[100000];
int D[100000],DD[100000],DDD[100000],res;
vector<edge>E[100000];

void dfs0(int x,int from,vector<int>&v){
	vis[x]=true;
	v.push_back(x);
	for(edge e:E[x]){
		if(e.to==from)continue;
		D[e.to]=D[x]+e.dist;
		dfs0(e.to,x,v);
	}
}

void dfs1(int x,int from){
	for(edge e:E[x]){
		if(e.to==from)continue;
		DD[e.to]=DD[x]+e.dist;
		dfs1(e.to,x);
	}
}
void dfs2(int x,int from){
	for(edge e:E[x]){
		if(e.to==from)continue;
		DDD[e.to]=DDD[x]+e.dist;
		dfs2(e.to,x);
	}
}


int travelTime(int N, int M, int L, int a[], int b[], int d[]) {
	for(int i=0;i<M;i++){
		E[a[i]].push_back({b[i],d[i]});
		E[b[i]].push_back({a[i],d[i]});
	}
	vector<int>v;
	for(int i=0;i<N;i++){
		if(!vis[i]){
			vector<int>V;
			dfs0(i,i,V);
			pair<int,int>p={-1,-1};
			for(int j:V){
				p=max(p,{D[j],j});
			}
			dfs1(p.second,p.second);
			pair<int,int>pp={-1,-1};
			for(int j:V){
				pp=max(pp,{DD[j],j});
			}
			dfs2(pp.second,pp.second);
			int mn=2000000000;
			for(int j:V){
				mn=min(mn,max(DD[j],DDD[j]));
			}
			res=max(res,pp.first);
			v.push_back(mn);
		}
	}
	sort(v.begin(),v.end(),greater<>());
	if(v.size()==1){
		return res;
	}
	else if(v.size()==2){
		return max(res,v[0]+v[1]+L);
	}
	else{
		return max({res,v[0]+v[1]+L,v[1]+v[2]+L+L});
	}
}

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23