Submission #1074380

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAX_N = 300030;    // Change as necessary
const ll  MODD = 1000000009; //

int A[MAX_N],B[MAX_N],C[MAX_N];

vector<int> adj[MAX_N];

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  
  int n; cin >> n;
  for(int i=1;i<n;i++){
    cin >> A[i]; A[i]--;
    B[A[i]]++;
  }
  
  queue<int> q;
  for(int i=0;i<n;i++)
    if(B[i] == 0)
      q.push(i);
  
  while(!q.empty()){
    int v = q.front(); q.pop();
    if(v == 0) break;
    C[v] = max(C[v],C[A[v]]);
    C[A[v]] = max(C[A[v]],C[v]+1);
    B[A[v]]--;
    if(B[A[v]] == 0)
      q.push(A[v]);
  }
  
  cout << C[0] << endl;
  
  return 0;
}

Submission Info

Judge Result