#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define f first
#define s second
const int mxN = 1e5+2;
vector<pii>chu[mxN];
vector<int>vis(mxN);
vector<int>nodes;
int dist[mxN][2];
void dfs(int curr, int prev, int d, int t){
nodes.push_back(curr);
vis[curr]=1;
dist[curr][t]=d;
for(pii next : chu[curr]){
if(next.f==prev)
continue;
dfs(next.f,curr,d+next.s,t);
}
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
for(int i = 0; i < M; i++){
chu[A[i]].push_back({B[i],T[i]});
chu[B[i]].push_back({A[i],T[i]});
}
int ans = 0;
vector<int>answer;
for(int i = 0; i < N; i++){
if(!vis[i]){
dfs(i,-1,0,0);
int u = i;
for(int n : nodes){
if(dist[n][0]>dist[u][0])
u=n;
}
nodes.clear();
dfs(u,-1,0,0);
int v = u;
for(int n : nodes){
if(dist[n][0]>dist[v][0])
v=n;
}
nodes.clear();
dfs(v,-1,0,1);
int temp = 1e9;
for(int n : nodes)
temp = min(temp,max(dist[n][0],dist[n][1]));
answer.push_back(temp);
ans = max(ans,dist[u][1]);
nodes.clear();
}
}
sort(answer.begin(),answer.end(),greater<int>());
if(answer.size()>=2)
ans = max(ans,answer[0]+answer[1]+L);
if(answer.size()>=3)
ans = max(ans,answer[1]+answer[2]+2*L);
return ans;
}
/*
int main(){
int a[] = {0, 8, 2, 5, 5, 1, 1, 10};
int b[] = {8, 2, 7, 11, 1, 3, 9, 6};
int c[] = {4, 2, 4, 3, 7, 1, 5, 3};
cout << travelTime(12,8,2,a,b,c);
}
*/
Compilation message
/tmp/cciay5uS.o: In function `main':
grader.c:(.text.startup+0xa7): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
