#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll N, M, L;
vector<pair<ll, ll>> G[100005];
ll V1[100005];
ll D = 0, E = 0;
pair<ll, ll> Dia[100005];
ll ans = 0;
pair<ll, ll> path[100005];
void dfs1(ll n, ll p, ll k){
V1[n] = 1;
if(D < k){
D = k;
E = n;
}
for(auto i : G[n]){
ll nx = i.first, c = i.second;
if(nx == p) continue;
dfs1(nx, n, k + c);
}
}
void dfs2(ll n, ll p, ll d){
if(n == d) return;
for(auto i : G[n]){
ll nx = i.first, c = i.second;
if(nx == p) continue;
path[nx] = {n, c};
dfs2(nx, n, d);
}
}
ll R[100005];
ll sum = 1e18;
ll cost = 0;
void track(ll n, ll s, ll i){
if(n == s) return;
ll nx = path[n].first, c = path[n].second;
sum = min(sum, max(R[i] - cost, cost));
cost += c;
track(nx, s, i);
}
int travelTime(int n, int m, int l, int A[], int B[], int T[]){
N = n, M = m, L = l;
for(int i = 0; i < M; i++){
ll u = A[i], v = B[i], c = T[i];
u++; v++;
G[u].push_back({v, c});
G[v].push_back({u, c});
}
fill(R + 1, R + N + 1, -1);
for(int i = 1; i <= N; i++){
if(V1[i]) continue;
D = -1;
dfs1(i, -1, 0);
D = -1;
Dia[i].first = E;
dfs1(E, -1, 0);
Dia[i].second = E;
R[i] = D;
ans = max(ans, D);
}
vector<ll> X;
for(int i = 1; i <= N; i++){
if(R[i] == -1) continue;
dfs2(Dia[i].first, -1, Dia[i].second);
sum = 1e18, cost = 0;
track(Dia[i].second, Dia[i].first, i);
if(Dia[i].first == Dia[i].second) sum = 0;
X.push_back(sum);
}
sort(X.begin(), X.end(), greater<ll>());
if(X.size() >= 2){
ans = max(ans, X[0] + X[1] + L);
}
if(X.size() >= 3){
ans = max(ans, X[1] + X[2] + 2 * L);
}
return ans;
}
Compilation message
/usr/bin/ld: /tmp/cccuc73P.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
