#include "towns.h"
#include<bits/stdc++.h>
using namespace std;
int hubDistance(int N, int sub) {
vector<int> d1(N, 0), d2(N, 0);
int bsf = 0, f1, f2;
for (int i=1; i<N; i++){
int d = getDistance(0, i);
if (d > bsf){
bsf = d;
f1 = i;
}
}
bsf = 0;
for (int i=0; i<N; i++){
if (i == f1) continue;
int d = getDistance(f1, i);
d1[i] = d;
if (d > bsf){
bsf = d;
f2 = i;
}
}
int R = pow(10, 9);
map<int,vector<int>> m;
for (int i=0; i<N; i++){
if (i == f1 || i == f2) continue;
int d = getDistance(f2, i);
d2[i] = d;
int l = (d1[i]+d2[i]-bsf)/2;
R = min(R, max(d1[i], d2[i])-l);
m[d1[i]-l].push_back(i);
}
return R;
bool bal = false;
for (auto it=m.begin(); it != m.end(); it++){
if (it->first == R || it->first == bsf-R){
int x1 = 1, x2 = 0, x3 = 1;
for (auto jt=m.begin(); jt != it; jt++) x1 += jt->second.size();
for (auto jt=next(it); jt != m.end(); jt++) x3 += jt->second.size();
set<pair<int,int>> s, d;
for (int v : it->second) s.insert({1, v});
while (s.size() > 1){
if (s.size() % 2){
d.insert(*s.begin());
s.erase(s.begin());
}
set<pair<int,int>> ns;
while (!s.empty()){
auto g1 = s.begin(), g2 = next(s.begin());
if (d1[g1->second]+d1[g2->second]-getDistance(g1->second, g2->second) > 2*it->first) ns.insert({g1->first+g2->first, g1->second});
else {
d.insert(*g1);
d.insert(*g2);
}
s.erase(s.begin());
s.erase(s.begin());
}
s = ns;
}
if (!s.empty()){
x2 = s.begin()->first;
for (auto [num, rep] : d){
if (d1[s.begin()->second]+d1[rep]-getDistance(s.begin()->second, rep) > 2*it->first) x2 += num;
}
}
//cout << x1 << " " << x2 << " " << x3 << endl;
if (x1 <= N/2 && x2 <= N/2 && x3 <= N/2) bal = true;
}
}
if (bal) return R;
else return -R;
}
