#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long int ll;
vector<vector<pair<int, int>>> g;
vector<bool>used;
vector<int>ans;
vector<pair<int, int>>dp;
int res=2e9;
void dfs1(int u){
used[u]=true;
for(pair<int, int> vec:g[u]){
int v=vec.first, c=vec.second;
if (used[v]) continue;
dfs1(v);
if (dp[u].first<dp[v].first+c){
dp[u].second=dp[u].first;
dp[u].first=dp[v].first+c;
}else if (dp[u].second<dp[v].first+c){
dp[u].second=dp[v].first+c;
}
}return;
}
void dfs2(int u, int p, int maxi){
int maxim=maxi;
res=min(res, max(maxim,dp[u].first));
for(pair<int, int> vec:g[u]){
int v=vec.first, c=vec.second;
if (v==p) continue;
if (dp[u].first==dp[v].first+c) maxi=max(maxim+c, dp[u].second+c);
else maxi=max(maxim, dp[u].first+c);
dfs2(v, u, maxi);
}return;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
g.resize(N);
used.assign(N, false);
dp.assign(N, {0, 0});
for (int i=0; i<M; i++){
g[A[i]].push_back({B[i], T[i]});
g[B[i]].push_back({A[i], T[i]});
}for (int i=0; i<N; i++){
if (used[i]) continue;
res=2e9;
dfs1(i);
dfs2(i, -1, 0);
ans.push_back(res);
}sort(ans.begin(), ans.end());
reverse(ans.begin(), ans.end());
if (ans.size()==1) return ans[0];
if (ans.size()==2) return ans[0]+ans[1]+L;
return max(ans[0]+ans[1]+L, ans[1]+ans[2]+2*L);
}
Compilation message
/usr/bin/ld: /tmp/cceqkCPT.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
