제출 #677255

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
677255		Cyanmond	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	93 ms	19496 KiB

catinatree

#include <bits/stdc++.h>

int main() {
    int N, D;
    std::cin >> N >> D;
    std::vector<int> P(N - 1);
    std::vector<std::vector<int>> tree(N);
    for (int i = 0; i < N - 1; ++i) {
        std::cin >> P[i];
        tree[P[i]].push_back(i + 1);
    }

    auto dfs = [&](auto &&self, const int v) -> std::pair<int, int> {
        if (tree[v].size() == 0) {
            return std::make_pair(1, 1);
        }
        std::vector<std::pair<int, int>> children;
        for (const int t : tree[v]) {
            children.push_back(self(self, t));
        }
        std::sort(children.begin(), children.end(), std::greater());
        const int m = (int)children.size();
        int lm = m - 1;
        for (int i = 1; i < m; ++i) {
            if (children[i].first + children[i - 1].first < D) {
                lm = i - 1;
                break;
            }
        }
        int sum = 0;
        for (const auto &[a, b] : children) {
            sum += b;
        }
        sum -= m - lm - 1;
        int nf = children[lm].first;
        if (nf >= D) {
            nf = 0;
            ++sum;
        }
        ++nf;
        return std::make_pair(nf, sum);
    };

    std::cout << dfs(dfs, 0).second << std::endl;
}

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