Submission #463920

#	Time	Username	Problem	Language	Result	Execution time	Memory
463920		blue	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	183 ms	93880 KiB

catinatree

#include <iostream>
#include <deque>
#include <vector>
using namespace std;

const int maxN = 200'000;
int N, D;
vector<int> children[maxN];

deque<int> dfs(int u)
{
    deque<int> res(1, 1);
    for(int v: children[u])
    {
        deque<int> add = dfs(v);
        add.push_front(add.front());

        if(res.size() < add.size()) swap(res, add);
        for(int i = 0; i < add.size(); i++)
        {
            int opt1 = add[i] + (D - i < res.size() ? res[max(D-i, i)] : 0);
            int opt2 = res[i] + (D - i < add.size() ? add[max(D-i, i)] : 0);
            res[i] = max(res[i], max(opt1, opt2));
        }

        for(int i = add.size(); i >= 0; i--)
        {
            if(i + 1 < res.size())
                res[i] = max(res[i], res[i+1]);
        }
    }
    return res;
}

int main()
{
    cin >> N >> D;

    for(int i = 1; i < N; i++)
    {
        int x;
        cin >> x;

        children[x].push_back(i);
    }

    deque<int> R = dfs(0);
    int res = 0;
    for(int r: R) res = max(res, r);
    cout << res << '\n';
}

Compilation message (stderr)

catinatree.cpp: In function 'std::deque<int> dfs(int)':
catinatree.cpp:19:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for(int i = 0; i < add.size(); i++)
      |                        ~~^~~~~~~~~~~~
catinatree.cpp:21:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |             int opt1 = add[i] + (D - i < res.size() ? res[max(D-i, i)] : 0);
      |                                  ~~~~~~^~~~~~~~~~~~
catinatree.cpp:22:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |             int opt2 = res[i] + (D - i < add.size() ? add[max(D-i, i)] : 0);
      |                                  ~~~~~~^~~~~~~~~~~~
catinatree.cpp:28:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |             if(i + 1 < res.size())
      |                ~~~~~~^~~~~~~~~~~~

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