제출 #1103131

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1103131		alexdd	Cat in a tree (BOI17_catinatree)	C++17	11 / 100	3 ms	7760 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e9;
int n,d,root,cnt;
vector<int> con[200005];
int parent[200005];
int insus[200005],injos[200005];
void dfs(int nod)
{
    insus[nod]=0;
    for(int adj:con[nod])
    {
        if(adj==parent[nod])
            continue;
        parent[adj] = nod;
        injos[adj] = max(injos[adj], injos[nod]-1);
        dfs(adj);
        insus[nod] = max(insus[nod], insus[adj]-1);
        injos[nod] = max(injos[nod], insus[adj]-1);
    }
    if(injos[nod]<=0 && insus[nod]<=0)
    {
        cnt++;
        insus[nod]=d;
    }
}
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;
    return 0;
}

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