#include<bits/stdc++.h>
using namespace std;
#define pb push_back
int n, ans = 3700000, a, b;
vector<vector<int>> g;
vector<int> dp;
multiset<int> s;
void dfs(int v, int p){
dp[v] = 1;
for(int u: g[v])
if(u != p) dfs(u, v), dp[v] += dp[u];
}
void dfs1(int v, int p){
auto it = s.lower_bound((n-dp[v]) / 2);
if(it == s.begin()){
if(it != s.end()){
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
}else{
if(it != s.end()){
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
--it;
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
for(int u: g[v]) if(u != p) dfs1(u, v);
s.insert(dp[v]);
}
void dfs2(int v, int p){
auto it = s.lower_bound((n-dp[v]) / 2);
if(it == s.begin()){
if(it != s.end()){
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
}else{
if(it != s.end()){
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
--it;
int x = *it, y = n-(dp[v]+x);
ans = min(ans, max({abs(x - dp[v]), abs(x - y), abs(y - dp[v])}));
}
s.insert(n - dp[v]);
for(int u: g[v]) if(u != p) dfs2(u, v);
s.erase(s.find(n-dp[v]));
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
cin >> n;
g.resize(n+1);
dp.resize(n+1);
for(int i=0; i < n-1; i++){
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
}
dfs(1, 0);
dfs1(1, 0);
s.clear();
dfs2(1, 0);
cout << ans;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
332 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
332 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
2 ms |
460 KB |
Output is correct |
7 |
Correct |
2 ms |
460 KB |
Output is correct |
8 |
Correct |
2 ms |
460 KB |
Output is correct |
9 |
Correct |
2 ms |
460 KB |
Output is correct |
10 |
Correct |
2 ms |
460 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
1 ms |
332 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
2 ms |
460 KB |
Output is correct |
7 |
Correct |
2 ms |
460 KB |
Output is correct |
8 |
Correct |
2 ms |
460 KB |
Output is correct |
9 |
Correct |
2 ms |
460 KB |
Output is correct |
10 |
Correct |
2 ms |
460 KB |
Output is correct |
11 |
Correct |
281 ms |
24156 KB |
Output is correct |
12 |
Correct |
302 ms |
24004 KB |
Output is correct |
13 |
Correct |
246 ms |
24372 KB |
Output is correct |
14 |
Correct |
261 ms |
24132 KB |
Output is correct |
15 |
Correct |
288 ms |
23968 KB |
Output is correct |
16 |
Correct |
200 ms |
24000 KB |
Output is correct |
17 |
Correct |
287 ms |
24184 KB |
Output is correct |
18 |
Correct |
269 ms |
29292 KB |
Output is correct |
19 |
Correct |
274 ms |
24264 KB |
Output is correct |
20 |
Correct |
306 ms |
24024 KB |
Output is correct |