Submission #230055

#	Time	Username	Problem	Language	Result	Execution time	Memory
230055		errorgorn	Dreaming (IOI13_dreaming)	C++14	100 / 100	117 ms	16628 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;
#define ii pair<int,int>

const int INF=2e9;

int n,m,l;
vector<ii> al[100005];
bool visited[100005];

vector<int> curr;
int w[3][100005];

vector<int> small;

void dfs(int i,int p,int id){
	if (id==0) curr.push_back(i);
	
	for (auto &it:al[i]){
		if (it.first==p) continue;
		
		w[id][it.first]=w[id][i]+it.second;
		dfs(it.first,i,id);
	}
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    n=N,m=M,l=L;
    
    for (int x=0;x<m;x++){
		al[A[x]].push_back(ii(B[x],T[x]));
		al[B[x]].push_back(ii(A[x],T[x]));
	}
	
	int ans=0;
	
	for (int x=0;x<n;x++){
		if (visited[x]) continue;
		
		curr.clear();
		
		w[0][x]=0;
		dfs(x,-1,0);
		
		for (auto &it:curr) visited[it]=true;
		
		for (auto &it:curr) if (w[0][it]>w[0][curr[0]]) swap(curr[0],it);
		w[1][curr[0]]=0;
		dfs(curr[0],-1,1);
		
		for (auto &it:curr) if (w[1][it]>w[1][curr[1]]) swap(curr[1],it);
		w[2][curr[1]]=0;
		dfs(curr[1],-1,2);
		
		ans=max(ans,w[2][curr[0]]);
		//cout<<w[2][curr[0]]<<endl;
		
		small.push_back(INF);
		for (auto &it:curr){
			small.back()=min(small.back(),max(w[1][it],w[2][it]));
		}
	}
	
	sort(small.begin(),small.end());
	reverse(small.begin(),small.end());
	
	if (small.size()>=2) ans=max(ans,small[0]+small[1]+l);
	if (small.size()>=3) ans=max(ans,small[1]+small[2]+l*2);
	
	return ans;
}

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