int maxCities(int n, vector<int> a, vector<int> b, vector<int> len) {
if (n <= 2) return n;
vector<vector<int>> adjNode(n);
for (int i = 0; i < n-1; ++i) {
--a[i];
--b[i];
adjNode[a[i]].push_back(b[i]);
adjNode[b[i]].push_back(a[i]);
distMap[{a[i], b[i]}] = len[i];
distMap[{b[i], a[i]}] = len[i];
}
int maxCount = 2;
for (int i = 0; i < n; ++i) {
Mii m;
for (int j : adjNode[i]) {
Si s;
// node, parent
ST<Pii> st;
Vi d(n, -1);
d[i] = 0;
st.emplace(j, i);
while (!st.empty()) {
Pii p = st.top();
d[p.first] = dist(p.first, p.second) + d[p.second];
s.insert(d[p.first]);
st.pop();
for (int k : adjNode[p.first]) {
if (k == p.second) continue;
st.emplace(k, p.first);
}
}
for (int dd : s) {
if (m.count(dd)) {
++m[dd];
} else m[dd] = 1;
}
}
for (Pii t : m) {
if (t.second > maxCount) maxCount = t.second;
}
}
return maxCount;
}
