#include "towns.h"
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pll;
#define all(x) (x).begin(), (x).end()
#define X first
#define Y second
#define sep ' '
#define debug(x) cerr << #x << ": " << x << endl;
const int MAXN = 300 + 10;
int n, D0[MAXN], D1[MAXN], diam, diam_v, diam_u;
inline int get(int u, int v) {
return getDistance(u, v);
}
inline int mirror_on_0u(int v) {
return (D1[v] - D0[v] + D0[diam_u]) / 2;
}
inline bool is_eq(int a, int b) {
return get(a, b) + D0[diam_u] < min(D0[a] + D1[b], D0[b] + D1[a]);
}
inline bool find_maj(vector<int> vec) {
if (int(vec.size()) <= n / 2) return false;
vector<pll> R;
int maj_cnt = 0;
int maj = -1;
if (vec.size() % 2 == 1) {
maj_cnt = 1;
maj = vec.back();
vec.pop_back();
R.push_back({maj, 1});
}
while (!vec.empty()) {
int a = vec.back();
vec.pop_back();
int b = vec.back();
vec.pop_back();
if (is_eq(a, b)) {
if (maj_cnt == 0) {
maj = a;
maj_cnt = 2;
} else if (maj_cnt == 1) {
maj = a;
maj_cnt = 1;
} else if (maj_cnt == 2) {
maj = -1;
maj_cnt = 0;
} else {
maj_cnt -= 2;
}
R.push_back({a, 2});
} else {
R.push_back({a, 1});
R.push_back({b, 1});
}
}
if (maj >= 0) {
int cnt = 0;
for (auto [x, w] : R)
if (x == maj || is_eq(maj, x))
cnt += w;
return cnt > n / 2;
}
return false;
}
// TODO: n / 2 tof
int hubDistance(int N_, int sub) {
memset(D0, 0, sizeof D0);
memset(D1, 0, sizeof D1);
n = N_;
for (int i = 1; i < n; i++)
D0[i] = get(0, i);
map<int, vector<int>> mp;
diam_u = max_element(D0, D0 + n) - D0;
D1[0] = D0[diam_u];
for (int i = 1; i < n; i++) {
if (i == diam_u) continue;
D1[i] = get(diam_u, i);
}
diam_v = max_element(D1, D1 + n) - D1;
diam = D1[diam_v];
int v_mir = mirror_on_0u(diam_v), r = numeric_limits<int>::max();
vector<int> cent;
for (int i = 0; i < n; i++) {
if (mirror_on_0u(i) > v_mir) continue;
int a = mirror_on_0u(i);
int b = D1[diam_v] - mirror_on_0u(i);
int tr = max(a, b);
if (tr < r) {
cent.clear();
cent.push_back(a);
r = tr;
} else if (tr == r) cent.push_back(a);
mp[a].push_back(i);
}
r = -r;
int ps = 0, ss = n;
for (auto [x, vec] : mp) {
ps -= vec.size();
if (find(all(cent), x) != vec.end())
if (!find_maj(vec))
r = abs(r);
ss += vec.size();
}
return r;
}
