#include "dreaming.h"
#include<bits/stdc++.h>
using namespace std;
vector<vector<pair<int ,int>>> adj;
vector<int> center;
vector<bool> vis;
vector<int> nodes;
void dfs1(int x , int p = -1)
{
nodes.push_back(x);
vis[x] = 1;
for(auto [u , c] : adj[x])
{
if(u == p)
continue;
dfs1(u , x);
}
}
vector<vector<int>> dist;
int dfs2(int x ,int i, int p = -1 , int d = 0)
{
dist[i][x] = d;
int opt = x;
for(auto [u , c] : adj[x])
{
if(u == p)
continue;
int n = dfs2(u , i , x , d + c);
if(dist[i][opt] < dist[i][n])
opt = n;
}
return opt;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[])
{
adj.assign(N , {});
vis.assign(N , 0);
for(int i = 0 ; i < M; i++)
{
adj[A[i]].push_back({B[i] , T[i]});
adj[B[i]].push_back({A[i] , T[i]});
}
dist.assign(2 , vector<int>(N , 0));
int ans = 0;
for(int i = 0 ; i < N ; i++)
{
if(!vis[i])
{
nodes.clear();
dfs1(i);
int x = dfs2(i , 0);
int y = dfs2(x , 0);
ans = max(ans , dist[0][y]);
dfs2(y , 1);
int mn = 2e9;
for(auto node : nodes)
{
mn = min(mn , max(dist[0][node] , dist[1][node]));
}
center.push_back(mn);
}
}
sort(center.rbegin(), center.rend());
if((int)center.size() > 1)
ans = max(ans , center[0] + center[1] + L);
if((int)center.size() > 2)
ans = max(ans , center[1] + center[2] + 2 * L);
return ans;
}
