#include<bits/stdc++.h>
#include "dreaming.h"
using namespace std;
const long long MAXN = 5e5 + 10;
vector < pair < long long, long long > > g[MAXN];
long long mark[MAXN];
long long used[MAXN];
void dfs0(long long beg)
{
mark[beg] = 1;
used[beg] = 1;
long long nb;
for (long long i = 0; i < g[beg].size(); ++ i)
{
nb = g[beg][i].first;
if(!used[nb])
dfs0(nb);
}
}
long long far = 0, far_index = 0;
void dfs_diam(int beg, int to_there)
{
if(far <= to_there)
{
far = to_there;
far_index = beg;
}
used[beg] = 1;
int nb, distt;
for (int i = 0; i < g[beg].size(); ++ i)
{
nb = g[beg][i].first;
distt = g[beg][i].second;
if(!used[nb])dfs_diam(nb, to_there + distt);
}
}
long long maxdist = 0;
long long dfs(long long beg)
{
used[beg] = 1;
long long nb, distt;
long long maxx = 0;
for (long long i = 0; i < g[beg].size(); ++ i)
{
nb = g[beg][i].first;
distt = g[beg][i].second;
if(!used[nb])maxx = max(maxx, dfs(nb)+distt);
}
return maxx;
}
vector < pair < long long, long long > > path;
long long st, fi;
long long marked[MAXN];
long long dfs_form(long long beg, long long add)
{
marked[beg] = 1;
used[beg] = 1;
if(beg == fi)
{
path.push_back(make_pair(beg, add));
return 1;
}
long long nb, distt;
long long found = 0;
for (long long i = 0; i < g[beg].size(); ++ i)
{
nb = g[beg][i].first;
distt = g[beg][i].second;
if(!used[nb])
{
if(dfs_form(nb, add + distt))found = 1;
}
}
if(found)path.push_back(make_pair(beg, add));
return found;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[])
{
for (long long i = 0; i < M; ++ i)
{
g[A[i]].push_back(make_pair(B[i], T[i]));
g[B[i]].push_back(make_pair(A[i], T[i]));
}
long long n = N;
priority_queue < pair < int/*diam*/, int > > pq;
for (int i = 0; i < n; ++ i)
{
if(marked[i])continue;
int aa1 = 0, bb1 = 0;
int aa2 = 0, bb2 = 0;
memset(used, 0, sizeof(used));
far = 0;
far_index = 0;
dfs_diam(i, 0);
aa1 = far_index;
memset(used, 0, sizeof(used));
far = 0;
far_index = 0;
dfs_diam(aa1, 0);
bb1 = far_index;
path.clear();
st = aa1;
fi = bb1;
memset(used, 0, sizeof(used));
dfs_form(st, 0);
long long index1 = path[0].first;
long long total1 = path[0].second;
long long best1 = total1, curr;
for (int i = 1; i < path.size(); ++ i)
{
curr = max(path[i].second, total1 - path[i].second);
if(curr < best1)
{
best1 = curr;
index1 = path[i].first;
}
}
pq.push(make_pair(best1, index1));
// cout << "component " << best1 << " " << index1 << endl;
}
int sz = pq.size();
while(pq.size() > 1)
{
int diam1 = pq.top().first;
int ii1 = pq.top().second;
pq.pop();
int diam2 = pq.top().first;
int ii2 = pq.top().second;
pq.pop();
int neww = max(max(diam1, diam2), min(diam1, diam2) + L);
g[ii1].push_back(make_pair(ii2, L));
g[ii2].push_back(make_pair(ii1, L));
if(diam1 > diam2)pq.push(make_pair(neww, ii1));
else pq.push(make_pair(neww, ii2));
}
int aa1 = 0, bb1 = 0;
int aa2 = 0, bb2 = 0;
memset(used, 0, sizeof(used));
far = 0;
far_index = 0;
dfs_diam(0, 0);
aa1 = far_index;
memset(used, 0, sizeof(used));
return dfs(aa1);
///
}
