Submission #1103136

#	Time	Username	Problem	Language	Result	Execution time	Memory
1103136		alexdd	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	47 ms	26188 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e9;
int n,d,root;
vector<int> con[200005];
int parent[200005];
int cnt[200005],injos[200005];
void dfs(int nod)
{
    cnt[nod]=1;
    injos[nod]=0;
    for(int adj:con[nod])
    {
        if(adj==parent[nod])
            continue;
        parent[adj]=nod;
        dfs(adj);
        cnt[nod] += cnt[adj];
        if(injos[nod]+injos[adj]+1 < d)
        {
            cnt[nod]--;
            injos[nod] = max(injos[nod], injos[adj]+1);
        }
        else
        {
            injos[nod] = min(injos[nod], injos[adj]+1);
        }
    }
}
signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n>>d;
    int u;
    for(int i=2;i<=n;i++)
    {
        cin>>u;
        u++;
        con[i].push_back(u);
        con[u].push_back(i);
    }
    root=1;
    for(int i=1;i<=n;i++)
        if((int)con[i].size()>1)
            root=i;
    //cerr<<root<<" root\n";
    dfs(root);
    cout<<cnt[root];
    return 0;
}

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