#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define double long double
using namespace std;
void db() {cerr << endl;}
template <typename T, typename ...U> void db(T a, U ...b) {
cerr << a << ' ', db(b...);
}
const int N = 2e5 + 1, inf = 1e9 + 1;
int n, ans = inf;
vector<int> g[N];
int sz[N];
multiset<int> s, s2;
void dfs1(int u, int p){
sz[u] = 1;
for (int i : g[u]){
if (i == p)
continue;
dfs1(i, u);
sz[u] += sz[i];
}
//db(u, sz[u]);
}
int f(int a, int b, int c){
return max({abs(a - b), abs(a - c), abs(b - c)});
}
void dfs(int u, int p){
auto it = s2.lower_bound((n + sz[u]) / 2);
if (it != s2.end())
ans = min(ans, f(sz[u], *it - sz[u], n - *it));
if (it != s2.begin()){
--it;
ans = min(ans, f(sz[u], *it - sz[u], n - *it));
}
auto it2 = s.lower_bound((n - sz[u]) / 2);
if (it2 != s.end())
ans = min(ans, f(sz[u], *it2, n - *it2 - sz[u]));
if (it2 != s.begin()){
--it2;
ans = min(ans, f(sz[u], *it2, n - *it2 - sz[u]));
}
s2.insert(sz[u]);
for (int i : g[u]){
if (i == p)
continue;
dfs(i, u);
}
s.insert(sz[u]);
s2.erase(s2.lower_bound(sz[u]));
}
int main(){
ios::sync_with_stdio(0), cin.tie(0);
cin >> n;
for (int i = 0; i < n - 1; i++){
int u, v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
dfs1(1, -1);
dfs(1, -1);
cout << ans << '\n';
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
5 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
5 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Correct |
4 ms |
5156 KB |
Output is correct |
7 |
Correct |
5 ms |
5196 KB |
Output is correct |
8 |
Correct |
5 ms |
5156 KB |
Output is correct |
9 |
Correct |
4 ms |
5196 KB |
Output is correct |
10 |
Correct |
5 ms |
5156 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
5 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Correct |
4 ms |
5156 KB |
Output is correct |
7 |
Correct |
5 ms |
5196 KB |
Output is correct |
8 |
Correct |
5 ms |
5156 KB |
Output is correct |
9 |
Correct |
4 ms |
5196 KB |
Output is correct |
10 |
Correct |
5 ms |
5156 KB |
Output is correct |
11 |
Correct |
262 ms |
21900 KB |
Output is correct |
12 |
Correct |
268 ms |
21808 KB |
Output is correct |
13 |
Correct |
235 ms |
22468 KB |
Output is correct |
14 |
Correct |
235 ms |
22196 KB |
Output is correct |
15 |
Correct |
290 ms |
21772 KB |
Output is correct |
16 |
Correct |
184 ms |
22592 KB |
Output is correct |
17 |
Correct |
271 ms |
21896 KB |
Output is correct |
18 |
Correct |
259 ms |
26124 KB |
Output is correct |
19 |
Correct |
241 ms |
22060 KB |
Output is correct |
20 |
Correct |
264 ms |
21796 KB |
Output is correct |