#include<bits/stdc++.h>
#define STIZE(x) fprintf(stderr, "STIZE%d\n", x);
#define PRINT(x) cerr << #x << '=' << x << endl;
#define NL(x) printf("%c", " \n"[(x)]);
#define lld long long
#define pii pair<int,int>
#define pb push_back
#define fi first
#define se second
#define mid (l+r)/2
#define endl '\n'
#define all(a) begin(a),end(a)
#define sz(a) int((a).size())
#define LINF 1000000000000000LL
#define INF 1000000000
#define EPS 1e-9
using namespace std;
#define MAXN 100010
vector<int> v, cur;
vector<pair<int,int> > adj[MAXN];
int pos[MAXN], dist1[MAXN], dist2[MAXN], rez;
void DFS1(int node, int prev, int dub, int dist[]) {
dist[node] = dub;
for(auto x : adj[node]) {
if(x.fi != prev) DFS1(x.fi, node, dub+x.se, dist);
}
}
void DFS2(int node, int prev) {
pos[node] = 1;
cur.pb(node);
for(auto x : adj[node]) {
if(x.fi != prev) DFS2(x.fi, node);
}
}
int handle(int node) {
cur.clear(); int X = MAXN-1, Y = MAXN-1, C = MAXN-1;
DFS2(node, node);
DFS1(node, node, 0, dist1);
for(auto x : cur) if(dist1[x] > dist1[X]) X = x;
DFS1(X, X, 0, dist1);
for(auto y : cur) if(dist1[y] > dist1[Y]) Y = y;
rez = max(rez, dist1[Y]);
DFS1(Y, Y, 0, dist2);
dist1[C] = dist2[C] = INF;
for(auto c : cur) if(max(dist1[c], dist2[c]) < max(dist1[C], dist2[C])) C = c;
dist1[MAXN-1] = dist2[MAXN-1] = 0;
return max(dist1[C], dist2[C]);
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
for(int i = 0; i < M; i++) {
adj[A[i]].pb({B[i], T[i]});
adj[B[i]].pb({A[i], T[i]});
}
for(int i = 0; i < N; i++) {
if(!pos[i]) v.pb(handle(i));
}
sort(all(v));
reverse(all(v));
if(sz(v) >= 2) rez = max(rez, v[0]+v[1]+L);
if(sz(v) >= 3) rez = max(rez, v[1]+v[2]+L+L);
return rez;
}
///
Compilation message
/tmp/ccDRT5Z7.o: In function `main':
grader.c:(.text.startup+0xa2): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
