Submission #3982322

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;
int main(){
  ll n;cin>>n;
  ll a[n];
  vector<ll>v[n];
  ll now[n];
  for(ll i=0;i<n;i++)now[i]=i;
  for(ll i=1;i<n;i++){
    cin>>a[i];
    a[i]--;
    v[now[a[i]]].push_back(i);
    now[a[i]]=i;
  }
  queue<pll> q;
  q.push(make_pair((ll)0,(ll)0));
  ll ans=0;
  while(q.size()>0){
    pll p=q.front();q.pop();
    ll pf=p.first,ps=p.second;
    ans=max(ans,ps);
    for(ll i=0;i<v[pf].size();i++){
      ll r=v[pf][i];
      q.push(make_pair(r,ps+1));
    }
  }
  cout<<ans<<endl;
}

Submission Info

Judge Result