Submission #1778594

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Source Code Expand

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
#define INF 1e9

typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<int> vi;
typedef vector < pair<int, int> > vii;
typedef long double ld;
typedef tree<pair<int,int>, null_type, less<pair<int,int> >, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<int>::iterator sit;
typedef map<int,int>::iterator mit;
typedef vector<int>::iterator vit;

ll n, x, par[100001], siz[100001], ans, cnt, dp[100001];
priority_queue<int, vector<int> > pq[100001];
queue <int> q;

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> n;
	for(int i = 2; i <= n; i++){
		cin >> par[i];
		siz[par[i]]++;
	}
	for(int i = 2; i <= n; i++){
		if(siz[i]==0){
			q.push(i);
		}
	}
	while(!q.empty()){
		x=q.front();
		q.pop();
		cnt=1;
		while(!pq[x].empty()){
			dp[x]=max(dp[x],pq[x].top()+cnt);
			cnt++;
			pq[x].pop();
		}
		pq[par[x]].push(dp[x]);
		siz[par[x]]--;
		if(siz[par[x]]==0 && x!=1){
			q.push(par[x]);
		}
	}
	cout << dp[1];
	return 0;
}

Submission Info

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