Submission #237236

#	Time	Username	Problem	Language	Result	Execution time	Memory
237236		IgorI	Cat in a tree (BOI17_catinatree)	C++17	51 / 100	280 ms	524292 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N = 200000;
const int K = 2000;

int n, d;
int dp[N][K];
int p[N];
vector<int> graph[N];

void dfs(int v)
{
    for (auto u : graph[v]) dfs(u);
    dp[v][0] = 1;
    for (auto u : graph[v]) dp[v][0] += dp[u][d - 1];
    for (int j = d; j > 0; j--)
    {
        if (2 * j >= d)
        {
            for (auto u : graph[v])
            {
                dp[v][j] += dp[u][j - 1];
            }
        }
        else
        {
            int allow = d - j - 1;
            dp[v][j] = dp[v][d - j];
            int r = 0;
            for (auto u : graph[v])
            {
                r = max(r, dp[u][j - 1] - dp[u][d - j - 1]);
            }
            dp[v][j] += r;
        }
    }
    for (int j = d - 1; j >= 0; j--) dp[v][j] = max(dp[v][j], dp[v][j + 1]);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> d;
    if (d == 1) cout << n, exit(0);
    for (int i = 1; i < n; i++)
    {
        cin >> p[i];
        graph[p[i]].push_back(i);
    }
    if (d < K)
    {
        dfs(0);
        cout << dp[0][0];
    }
    else
    {
        cout << 1;
    }
}

Compilation message (stderr)

catinatree.cpp: In function 'void dfs(int)':
catinatree.cpp:31:17: warning: unused variable 'allow' [-Wunused-variable]
             int allow = d - j - 1;
                 ^~~~~

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 0 / 49