oj.uz

답안 #494985

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
494985 2021-12-17T19:40:44 Z Victor Papričice (COCI20_papricice) C++17
0 / 110
 8 ms 14416 KB 
// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize ("Ofast,inline") // O1 - O2 - O3 - Os - Ofast
// #pragma GCC optimize ("unroll-loops")
#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;

const int INF = 1'000'000'007;

int n, ans = INF, sub_size[200001], root;
set<int> nodes[200001];
vi graph[200001];

void dfs(int u, int p) {
    sub_size[u] = 1;
    nodes[u].clear();
    trav(v, graph[u]) if (v != p) {
        dfs(v, u);
        sub_size[u] += sub_size[v];
        if (sz(nodes[u]) < sz(nodes[v])) nodes[u].swap(nodes[v]);
        trav(val, nodes[v]) nodes[u].insert(val);
        nodes[v].clear();
    }

    trav(v, graph[u]) if (v != p) nodes[u].insert(sub_size[v]);

    if (u != root && sub_size[u]) {
        int above = n - sub_size[u];
        int p1 = *nodes[u].lower_bound(sub_size[u] / 2), p2 = sub_size[u] - p1;
        int mx = max(above, max(p1, p2)), mn = min(above, min(p1, p2));
        ans = min(ans, mx - mn);
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    cin >> n;
    rep(i, 1, n) {
        int u, v;
        cin >> u >> v;
        graph[--u].pb(--v);
        graph[v].pb(u);
    }

    rep(i, 0, 50) {
        root = rand() % n;
        dfs(root, root);
    }

    cout << ans << endl;
    return 0;
}

Subtask #1
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 14284 KB Output is correct
2 Correct 8 ms 14412 KB Output is correct
3 Incorrect 8 ms 14416 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 14284 KB Output is correct
2 Correct 8 ms 14412 KB Output is correct
3 Incorrect 8 ms 14416 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 14284 KB Output is correct
2 Correct 8 ms 14412 KB Output is correct
3 Incorrect 8 ms 14416 KB Output isn't correct
4 Halted 0 ms 0 KB -