#include <bits/stdc++.h>
#define pii pair<int, int>
#define f first
#define s second
#define up(i, a, b) for (int i = (a); i <= (b); i++)
#define pb push_back
using namespace std;
const int oo = 2*1000000001;
const int maxn = 100001;
vector<pii> a[maxn];
int n,m,L;
bool dd[maxn];
int maxx = -1;
vector<int> luu;
int P = 0;
void DFS(int u, int parent, int d[]){
if (!dd[u]) luu.emplace_back(u);
dd[u] = 1;
for (pii x : a[u]){
int v = x.f;
int w = x.s;
if (v == parent) continue;
d[v] = d[u] + w;
DFS(v, u, d);
}
if (d[P] < d[u]) P = u;
maxx = max(maxx, d[u]);
}
int cost[maxn];
int dx[maxn];
int dy[maxn];
vector<int> R;
void find_center(int root){
P = 0;
DFS(root, -1, cost);
int X = P;
P = 0;
DFS(X, -1, dx);
int Y = P;
DFS(Y, -1, dy);
int minn = oo;
for (int i : luu){
minn = min(minn, max(dx[i], dy[i]));
cost[i] = dx[i] = dy[i] = 0;
}
luu.clear();
R.push_back(minn);
}
int travelTime(int n, int m, int L, int AA[], int BB[], int TT[]){
up(i, 0, m-1){
int u = AA[i];
u++;
int v = BB[i];
v++;
int w = TT[i];
a[u].pb(make_pair(v, w));
a[v].pb(make_pair(u, w));
}
if (m == n-1){
P = 0;
DFS(1, -1, cost);
int X = P;
P = 0;
fill(cost, cost+n+1, 0);
DFS(X, -1, cost);
return cost[P];
}
up(root, 1, n){
if (!dd[root]){
find_center(root);
}
}
int tplt = R.size();
sort(R.begin(), R.end(), greater<int>());
if (tplt > 1){
maxx = max(maxx, R[0] + R[1] + L);
}
if (tplt > 2){
maxx = max(maxx, R[1] + R[2] + L*2);
}
return maxx;
}
Compilation message
/usr/bin/ld: /tmp/ccLyCGNH.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status
