#include <bits/stdc++.h>
using namespace std;
int dist[100001], pre[100001]; bool vis[100001];
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
int maxDiameter = 0;
vector<int> radius;
vector<pair<int, int>> adj[N];
for (int i = 0; i < M; i++){
adj[A[i]].push_back(make_pair(T[i], B[i]));
adj[B[i]].push_back(make_pair(T[i], A[i]));
}
for (int i = 0; i < N; i++){
if (!vis[i]){
int maxd = 0, far = i, cur;
queue<pair<int, int>> q;
q.push(make_pair(i, 0));
vector<int> clean;
vis[i] = 1;
clean.push_back(i);
while(!q.empty()){
int p = q.front().first, d = q.front().second; q.pop();
if (d > maxd){
maxd = d;
far = p;
}
for (auto v : adj[p]){
if (!vis[v.second]){
vis[v.second] = 1;
clean.push_back(v.second);
q.push(make_pair(v.second, v.first + d));
}
}
}
for (int e : clean) vis[e] = 0;
maxd = 0; q.push(make_pair(far, 0)); cur = far;
vis[far] = 1;
while(!q.empty()){
int p = q.front().first, d = q.front().second; q.pop();
if (d > maxd){
maxd = d;
far = p;
}
for (auto v : adj[p]){
if (!vis[v.second]){
vis[v.second] = 1;
pre[v.second] = p;
dist[v.second] = v.first;
q.push(make_pair(v.second, v.first + d));
}
}
}
int r = maxd;
maxDiameter = max(maxDiameter, maxd);
for (int x = 0; far != cur; far = pre[far]){
r = min(r, max(maxd - x, x));
x += dist[far];
}
radius.push_back(r);
}
}
sort(radius.begin(), radius.end());
int S = radius.size();
if (S == 1) return maxDiameter;
int a = radius[S - 1] + radius[S - 2] + L, b = radius[S - 2] + radius[S - 3] + 2 * L;
if (S == 2) return max(maxDiameter, a);
return max(a, max(b, maxDiameter));
}
Compilation message
/tmp/ccTouRYN.o: In function `main':
grader.c:(.text.startup+0xa2): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
