#include <bits/stdc++.h>
#define maxn (int)(1e5+51)
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define ll long long
#define pb push_back
#define ull unsigned long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define inf 2000000001
#define mod 1000000007 //998244353
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
using namespace std;
template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }
vector<ii>g[maxn];
int vis[maxn];
ii farthest;
void dfs(int u,int p,int d,bool type){//acha maior caminho
vis[u] = type;
if(ckmax(farthest.second,d))farthest.first = u;
for(auto [d2,v]:g[u]){
if(v!=p)dfs(v,u,d+d2,type);
}
}
int dfs2(int u,int p,int target,int weight,int totweight){//acha centro
if(u==target)return -1;
for(auto [w,v]:g[u]){
if(v==p)continue;
int acc = dfs2(v,u,target,w,totweight);
if(acc){
acc = max(0,acc);
if(ckmin(farthest.second,max(acc+w,totweight-acc-w)))farthest.first = u;
return acc+w;
}
}
return 0;
}
vector<int>centros;
int travelTime(int n,int m,int l,int a[],int b[],int t[]){
for(int i=0;i<m;i++){
g[a[i]].pb({t[i],b[i]});
g[b[i]].pb({t[i],a[i]});
}
//achar centro de todas as componentes
//unir centro das componentes
// usar u, usar v
//ao unir, novo centro = min(max(d(v)+l,d(u)),max(d(u)+l,d(v)))
//fixar uma arvore e unir todas as restantes a partir dela
for(int i=0;i<n;i++){
if(!vis[i]){
farthest = {i,0};
dfs(i,i,0,0);
farthest.second = 0;
int u = farthest.first;
dfs(u,u,0,1);
int v = farthest.first;
dfs2(u,u,v,0,farthest.second);
centros.pb(farthest.first);
}
}
int central = centros[0];
for(int i=1;i<sz(centros);i++){
g[central].pb({l,centros[i]});
g[centros[i]].pb({l,central});
}
farthest = {0,0};
dfs(0,0,0,0);
farthest.second = 0;
dfs(farthest.first,farthest.first,0,0);
return farthest.second;
}
// int a[maxn],b[maxn],t[maxn];
// int main(){
// int n,m,l;cin>>n>>m>>l;
// for(int i=1;i<=m;i++)cin>>a[i-1]>>b[i-1]>>t[i-1];
// cout<<travelTime(n,m,l,a,b,t)<<endl;
// }
Compilation message
/usr/bin/ld: /tmp/cccYdRL0.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
