#include "dreaming.h"
#include <bits/stdc++.h>
#define s second
#define f first
#define pb push_back
#define ll long long
using namespace std;
const int N = 100005;
vector <pair<int,ll> > v[N];
vector <ll> vec;
int fix[N],I;
ll D,R,dis[N][5];
void dfs(int x,ll d,int par,int k){
fix[x] = 1;
if (d > D) {I = x,D = d;}
for (int j=0;j<v[x].size();j++){
int to = v[x][j].f,w = v[x][j].s;
if (to == par) continue;
if (k) dis[to][k] = dis[x][k] + w;
if (k == 2) {
R = min(R,max(dis[x][1],dis[x][2]));
// cout<<"x = "<<x<<" "<<dis[x][1]<<" "<<dis[x][2]<<endl;
}
dfs(to,d + w,x,k);
}
}
bool cmp(int a,int b){
if (a > b) return 1;
return 0;
}
int travelTime(int n, int m, int L, int A[], int B[], int T[]) {
for (int i = 0; i < m; i++){
v[A[i]].pb({B[i],T[i]});
v[B[i]].pb({A[i],T[i]});
}
ll ans=0;
for (int i = 0; i < n; i++){
if (fix[i])continue;
if (!v[i].size()){
fix[i]=1;
vec.pb(0);
continue;
}
D = 0;
dfs(i,0,i,0);
D = 0;
int ind = I;
dfs(ind,0,ind,1);
D = 0;
dfs(ind,0,ind,0);
D = 0;
R = 1e9;
dfs(I,0,I,2);
ans = max(D,ans);
vec.pb(R);
}
sort(vec.begin(),vec.end(),cmp);
if (vec.size() >= 2) ans = max(ans,vec[0] + vec[1] + L);
if (vec.size() >= 3) ans = max(ans,vec[1] + vec[2] + 2*L);
return ans;
}
