#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
#define SZ(x) int(x.size())
const int MXN = 1e5+5;
vector<pii> g[MXN];
int dp[MXN];
bool vis[MXN];
vector<int> vec;
void dfs(int v, int p=-1) {
vis[v] = 1;
vec.push_back(v);
for(auto [u, w] : g[v])
if(u != p) {
dfs(u, v);
dp[v] = max(dp[v], dp[u]+w);
}
}
void reroot(int v, int p=-1) {
int mx1 = 0, mx2 = -1e9;
for(auto [u, w] : g[v]) {
int val = dp[u] + w;
if(val>mx2) mx2=val;
if(mx2>mx1) swap(mx1, mx2);
}
for(auto [u, w] : g[v])
if(u!=p) {
int val = dp[u] + w;
dp[v] = val==mx1 ? mx2 : mx1;
reroot(u, v);
}
dp[v] = mx1;
}
int travelTime(int n, int m, int l, int A[], int B[], int T[]) {
for(int i=0; i<m; i++) {
g[A[i]].push_back({B[i], T[i]});
g[B[i]].push_back({A[i], T[i]});
}
vector<int> diams;
for(int i=0; i<n; i++)
if(!vis[i]) {
dfs(i);
reroot(i);
int res=2e9;
for(int v : vec)
res = min(res, dp[v]);
diams.push_back(res);
vec.clear();
}
sort(diams.begin(), diams.end());
int ans = *max_element(dp, dp+n);
if(SZ(diams)>=2) ans = max(ans, diams[SZ(diams)-1]+diams[SZ(diams)-2]+l);
if(SZ(diams)>=3)
ans = max(ans, diams[SZ(diams)-2]+diams[SZ(diams)-3]+l+l);
return ans;
}
