oj.uz

답안 #986518

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
986518 2024-05-20T17:42:24 Z HiepVu217 Papričice (COCI20_papricice) C++17
0 / 110
 3 ms 4964 KB 
#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
const int oo = 1e9;
#define sz(a) (int)a.size()
#define eb emplace_back
using pii = pair<int, int>;
int n;
 
namespace arcv {
    int n;
    vector<int> adj[N];
    int par[N];
    int sz[N];
    int st[N];
    int en[N];
    int tour[N];
    int ans = oo;
    int times = 0;
    multiset<int> S;
 
    void calc_sz(int u, int p) {
        par[u] = p;
        sz[u] = 1;
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            calc_sz(v, u);
            sz[u] += sz[v];
        }
    }
 
    int get(int a, int b, int c) {
        return max({a, b, c}) - min({a, b, c});
    }
 
    void DFS1(int u, int p) {
        auto it = S.lower_bound((n - sz[u]) / 2);
 
        if(it != S.end())
            ans = min(ans, get(sz[u], *it, n - sz[u] - (*it)));
 
        if(it != S.begin())
            --it;
 
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            DFS1(v, u);
        }
 
        S.emplace(sz[u]);
        en[u] = times;
    }
 
    void DFS2(int u, int p) {
        auto it = S.lower_bound((n + sz[u]) / 2);
 
        if(it != S.end())
            ans = min(ans, get((*it) - sz[u], sz[u], n - (*it)));
 
        if(it != S.begin())
            --it;
 
        if(it != S.end())
            ans = min(ans, get((*it) - sz[u], sz[u], n - (*it)));
 
        S.emplace(sz[u]);
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            DFS2(v, u);
        }
 
        S.erase(S.find(sz[u]));
    }
 
    void solution() {
        cin >> n;
 
        for(int i = 1; i < n; i++) {
            int u, v;
            cin >> u >> v;
            adj[u].eb(v);
            adj[v].eb(u);
        }
 
        calc_sz(1, 0);
        DFS1(1, 0);
        S.clear();
        DFS2(1, 0);
 
        cout << ans;
    }
}
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    arcv::solution();
}

Subtask #1
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4956 KB Output is correct
2 Correct 2 ms 4956 KB Output is correct
3 Incorrect 3 ms 4964 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4956 KB Output is correct
2 Correct 2 ms 4956 KB Output is correct
3 Incorrect 3 ms 4964 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4956 KB Output is correct
2 Correct 2 ms 4956 KB Output is correct
3 Incorrect 3 ms 4964 KB Output isn't correct
4 Halted 0 ms 0 KB -