#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
typedef struct {int to, cost;} edge;
vector<edge> G[100010], T(100010);
vector<int> rad;
bool done[100010];
int N, M, L, tmp, sz[100010], u, D;
int find(int v, bool trace=false, int p=-1, int d=0){
done[v]=true;
if(tmp<d) tmp=d, u=v;
int mx=0;
for(auto& e:G[v]){
if(e.to==p) continue;
int down=find(e.to, false, v, d+e.cost)+e.cost;
if(down>mx) mx=down, T[v]=e;
}
return mx;
}
int findcen(int v){
tmp=-1, find(v); int a=u;
tmp=-1, T.clear(), find(a,true); int b=u, dia=tmp, now=0;
while(a!=b){
int nxt=now+T[a].cost;
if(nxt<=dia-nxt){
a=T[a].to, now=nxt; continue;
}
if(max(now, dia-now)>max(nxt, dia-nxt))
a=T[a].to;
break;
}
return a;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
for(int i=0; i<M; i++){
G[A[i]+1].push_back({B[i]+1, T[i]});
G[B[i]+1].push_back({A[i]+1, T[i]});
}
for(int i=1; i<=N; i++)
if(!done[i]){
int c=findcen(i);
tmp=-1, find(c), rad.push_back(tmp);
tmp=-1, find(u), D=max(D, tmp);
}
sort(rad.begin(), rad.end(), greater<int>());
if(rad.size()>1U) D=max(D, rad[0]+rad[1]+L);
if(rad.size()>2U) D=max(D, rad[1]+rad[2]+2*L);
return D;
}
