Submission #731597

#	Time	Username	Problem	Language	Result	Execution time	Memory
731597		adrilen	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	61 ms	19112 KiB

catinatree

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
typedef pair<int, int> pii;
constexpr int maxn = 2e5;

basic_string <int> children[maxn];
int d;



pii dfs(int p)
{
    vector <pii> childs;

    if (children[p].size() == 0)
    {
        return pii(1, 1); // Dist, num
    }

    for (int i : children[p])
    {
        childs.emplace_back(dfs(i));
    }
    childs.emplace_back(0, 1);

    sort(childs.begin(), childs.end());

    pii out = pii(d + 1, 0);

    pii pot;
    while (!childs.empty())
    {
        pot = childs.back();
        childs.pop_back();

        if (pot.first + out.first >= d)
        {
            out.second += pot.second;
            out.first = pot.first;
        } else break;
    }

    out.second += pot.second - 1;

    while (!childs.empty())
    {
        pot = childs.back();
        childs.pop_back();

        out.second += pot.second - 1;
    }

    out.first ++;
    return out;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int n;
    cin >> n >> d;

    int a;
    for (int i = 1; i < n; i++)
    {
        cin >> a;
        children[a].push_back(i);
    }
    
    int root = 0;

    pii output = dfs(root);
    cout << output.second << "\n";
}

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