제출 #714911

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
714911		MilosMilutinovic	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	110 ms	28080 KiB

catinatree

#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n, k;
    std::cin >> n >> k;

    std::vector<std::vector<int>> adj(n);
    for (int i = 1; i < n; i++) {
        int p;
        std::cin >> p;
        adj[p].push_back(i);
        adj[i].push_back(p);
    }

    std::function<std::pair<int, int>(int, int)> Dfs = [&](int v, int pv) {
        std::vector<int> dist(1, 0);
        int f = 1;
        for (int u : adj[v]) {
            if (u == pv) {
                continue;
            }
            std::pair<int, int> x = Dfs(u, v);
            f += x.first;
            dist.push_back(x.second);
        }
        std::sort(dist.begin(), dist.end());
        std::reverse(dist.begin(), dist.end());
        while (dist.size() > 1 && dist.back() + dist[dist.size() - 2] < k) {
            dist.pop_back();
            f -= 1;
        }
        return std::make_pair(f, dist.back() + 1);
    };

    std::cout << Dfs(0, 0).first << "\n";

    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 49 / 49