Submission #1038991

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038991		Hanksburger	Cat in a tree (BOI17_catinatree)	C++17	0 / 100	1 ms	5208 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
int deg[200005], visited[200005], n, d, ans;
vector<int> adj[200005];
queue<int> q;
void dfs(int u, int x, int y)
{
    visited[u]=y;
    for (int v:adj[u])
    {
        if (visited[v]!=y && x<d)
            dfs(v, x+1, y);
        else if (!visited[v])
        {
            deg[v]--;
            if (deg[v]==1)
                q.push(v);
        }
    }
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> d;
    for (int i=1; i<n; i++)
    {
        int x;
        cin >> x;
        adj[i].push_back(x);
        adj[x].push_back(i);
        deg[i]++, deg[x]++;
    }
    for (int i=0; i<n; i++)
        if (deg[i]==1)
            q.push(i);
    while (!q.empty())
    {
        int u=q.front();
        q.pop();
        if (visited[u])
            continue;
        ans++;
        dfs(u, 1, u+1);
    }
    cout << ans;
}

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