/*
* ## ##### #### #### # # ####
* # # # # # # # # # # # #
* # # ##### # # # # # # #
* ###### # # # # # # ## # # #
* # # # # # # # # ## ## # #
* # # ##### #### #### # # ####
*/
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair <int, int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define info() cerr << __PRETTY_FUNCTION__ << ": " << __LINE__ << endl
void abc() {cerr << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
cerr << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
return o >> a.X >> a.Y;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
return o << '(' << a.X << ", " << a.Y << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
bool is = false;
for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
return o << '}';
}
template <typename T> struct vv : vector <vector <T>> {
vv(int n, int m, T v) : vector <vector <T>> (n, vector <T>(m, v)) {}
vv() {}
};
template <typename T> struct vvv : vector <vv <T>> {
vvv(int n, int m, int k, T v) : vector <vv <T>> (n, vv <T>(m, k, v)) {}
vvv() {}
};
#ifdef Doludu
#define test(args...) info(), abc("[" + string(#args) + "]", args)
#define owo void(0)
#else
#define test(args...) void(0)
#define owo ios::sync_with_stdio(false); cin.tie(0)
#endif
const int mod = 1e9 + 7, N = 200001, logN = 18, K = 1000;
vector <int> adj[N];
int sz[N];
void dfs_sz(int v, int pa) {
sz[v] = 1;
for (int u : adj[v]) if (u != pa) {
dfs_sz(u, v);
sz[v] += sz[u];
}
}
int ans = 1 << 30, n;
void calc(int a, int b, int c) {
if (a && b && c) ans = min(ans, max({a, b, c}) - min({a, b, c}));
}
multiset <int> pq[N];
void dfs_ans(int v, int pa) {
for (int u : adj[v]) if (u != pa) {
dfs_ans(u, v);
if (pq[v].size() < pq[u].size()) swap(pq[v], pq[u]);
for (int i : pq[u]) {
auto it = pq[v].lower_bound((i + 1) / 2);
if (it != pq[v].end()) calc(i, *it, n - i - *it);
if (it != pq[v].begin()) calc(i, *--it, n - i - *it);
}
for (int i : pq[u]) pq[v].insert(i);
}
auto it = pq[v].lower_bound((sz[v] + 1) / 2);
if (it != pq[v].end()) calc(n - sz[v], *it, sz[v] - *it);
if (it != pq[v].begin()) calc(n - sz[v], *--it, sz[v] - *it);
pq[v].insert(sz[v]);
}
int main () {
owo;
cin >> n;
for (int i = 0, u, v; i < n - 1; ++i) {
cin >> u >> v, --u, --v;
adj[u].pb(v);
adj[v].pb(u);
}
dfs_sz(0, -1);
dfs_ans(0, -1);
cout << ans << endl;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
8 ms |
14384 KB |
Output is correct |
| 2 |
Incorrect |
8 ms |
14408 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
8 ms |
14384 KB |
Output is correct |
| 2 |
Incorrect |
8 ms |
14408 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
8 ms |
14384 KB |
Output is correct |
| 2 |
Incorrect |
8 ms |
14408 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
