Submission #887854

#	Time	Username	Problem	Language	Result	Execution time	Memory
887854		amirhoseinfar1385	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	95 ms	21704 KiB

catinatree

#include<bits/stdc++.h>
using namespace std;
int n,d;
const int maxn=200000+10;
int dp[maxn];
vector<int>adj[maxn];
vector<pair<int,int>>alln;
void pre(int u=0,int len=0,int par=-1){
	alln.push_back(make_pair(len,u));
	for(auto x:adj[u]){
		if(x!=par){
			pre(x,len+1,u);
		}
	}
}
int res=0;
void upd(int u,int len,int par=-1){
	if(len<0||len<=dp[u]){
		return ;
	}
	dp[u]=len;
	for(auto x:adj[u]){
		if(x!=par){
			upd(x,len-1,u);
		}
	}
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>d;
	d--;
	for(int i=1;i<=n-1;i++){
		int f;
		cin>>f;
		adj[f].push_back(i);
		adj[i].push_back(f);
	}
	for(int i=0;i<n;i++){
		dp[i]=-1;
	}
	pre();
	sort(alln.rbegin(),alln.rend());
	for(int i=0;i<n;i++){
		//cout<<alln[i].first<<" "<<alln[i].second<<" "<<dp[alln[i].second]<<"\n";
		if(dp[alln[i].second]==-1){
			res++;
			upd(alln[i].second,d);
		}
	}
	cout<<res<<"\n";
}

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