# include <bits/stdc++.h>
# define pb push_back
# define ff first
# define ss second
# define nl "\n"
# define sz(x) ((int)(x).size())
# define deb(x) cerr << #x << " = " << x << endl;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
const ll maxn = 2e5 + 25;
const ll inf = 2e9 + 0;
const ll mod = 1e9 + 7;
const ll dx[] = {-1, 1, 0, 0};
const ll dy[] = {0, 0, -1, 1};
using namespace std;
int n, ans = inf;
vector <int> g[maxn];
int sz[maxn];
bool used[maxn];
multiset <int> a, b;
void dfs_calc (int v)
{
sz[v] = 1;
for (int to : g[v])
{
if (!sz[to])
{
dfs_calc(to);
sz[v] += sz[to];
}
}
}
vector <int> f (multiset <int>& s, int x)
{
vector <int> res;
auto it = s.lower_bound(x);
if (it != s.end())
{
res.pb(*it);
}
if (it != s.begin())
{
it--;
res.pb(*it);
}
return res;
}
int mx_mn (int x, int y, int z)
{
return max({x, y, z}) - min({x, y, z});
}
void dfs (int v)
{
used[v] = 1;
for (int x : f(a, (n + sz[v]) / 2))
{
ans = min(ans, mx_mn(sz[v], x - sz[v], n - x));
}
for (int x : f(b, n - sz[v] * 2))
{
ans = min(ans, mx_mn(sz[v], x, n - x - sz[v]));
}
a.insert(sz[v]);
for (int to : g[v])
{
if (!used[to])
{
dfs(to);
}
}
a.erase(a.find(sz[v]));
b.insert(sz[v]);
}
void ma1n (/* SABR */)
{
cin >> n;
for (int i = 1, u, v; i < n; ++i)
{
cin >> u >> v;
g[u].pb(v);
g[v].pb(u);
}
dfs_calc(1);
dfs(1);
cout << ans;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
// freopen("file.in", "r", stdin);
// freopen("file.out", "w", stdout);
int ttt = 1;
// cin >> ttt;
for (int test = 1; test <= ttt; ++test)
{
// cout << "Case " << test << ":" << ' ';
ma1n();
}
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
4948 KB |
Output is correct |
2 |
Correct |
3 ms |
4948 KB |
Output is correct |
3 |
Correct |
3 ms |
5024 KB |
Output is correct |
4 |
Correct |
3 ms |
5028 KB |
Output is correct |
5 |
Correct |
3 ms |
5020 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
4948 KB |
Output is correct |
2 |
Correct |
3 ms |
4948 KB |
Output is correct |
3 |
Correct |
3 ms |
5024 KB |
Output is correct |
4 |
Correct |
3 ms |
5028 KB |
Output is correct |
5 |
Correct |
3 ms |
5020 KB |
Output is correct |
6 |
Incorrect |
5 ms |
5212 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
4948 KB |
Output is correct |
2 |
Correct |
3 ms |
4948 KB |
Output is correct |
3 |
Correct |
3 ms |
5024 KB |
Output is correct |
4 |
Correct |
3 ms |
5028 KB |
Output is correct |
5 |
Correct |
3 ms |
5020 KB |
Output is correct |
6 |
Incorrect |
5 ms |
5212 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |