Submission #1272897

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272897		elotelo966	Cat in a tree (BOI17_catinatree)	C++20	100 / 100	190 ms	169712 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
 
//#define int long long
#define OYY LLONG_MAX
#define faster ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define fi first
#define se second
#define FOR for(int i=1;i<=n;i++)
#define mid (start+end)/2
#define pb push_back
#define lim 200005

typedef long long lo;

int n,d;

int cev;

vector<int> v[lim];

deque<int> dp[lim];

inline bool ch(int node,int dist){
	return  dist>=0 && (int)dp[node].size()-1>=dist;
}

inline void f(int node){
	dp[node].pb(1);
	int kim=-1,mx_sz=1;
	for(auto go:v[node]){
		f(go);
		if(ch(go,d-1))dp[node][0]+=dp[go][d-1];
		if(mx_sz<=(int)dp[go].size()){
			mx_sz=(int)dp[go].size();
			kim=go;
		}
	}
	
	int cur=0;
	
	for(auto go:v[node]){
		if(go==kim)continue;
		cur=max(cur,(int)dp[go].size());
	}
	
	if(~kim){
		dp[kim].push_front(dp[node][0]);
		swap(dp[kim],dp[node]);
	}
	
	vector<int> gec(cur+1,0);
		
	for(int j=1;j<=cur;j++){
		int tot=0,tot2=0,maxi=0;
		for(auto go:v[node]){
			if(kim==go){
				if(ch(node,d-j))tot+=dp[node][d-j];
				if(ch(node,j))tot2+=dp[node][j];
				if(ch(node,j))maxi=max(maxi,dp[node][j]);
				continue;
			}
			if(ch(go,d-j-1))tot+=dp[go][d-j-1];
			if(ch(go,j-1))tot2+=dp[go][j-1];
			if(ch(go,j-1))maxi=max(maxi,dp[go][j-1]);
		}
		for(auto go:v[node]){
			if(kim==go){
				if(ch(node,d-j))tot-=dp[node][d-j];
				if(ch(node,j))tot+=dp[node][j];
				if(ch(node,j) && j<=d-j)gec[j]=max(gec[j],tot);
				if(ch(node,j))tot-=dp[node][j];
				if(ch(node,d-j))tot+=dp[node][d-j];
				continue;
			}
			if(ch(go,d-j-1))tot-=dp[go][d-j-1];
			if(ch(go,j-1))tot+=dp[go][j-1];
			if(ch(node,j) && j<=d-j)gec[j]=max(gec[j],tot);
			if(ch(go,j-1))tot-=dp[go][j-1];
			if(ch(go,d-j-1))tot+=dp[go][d-j-1];
		}
		if(j>=d-j){
			gec[j]=max(gec[j],tot2);
		}
	}
	
	for(int j=cur;j>=0;j--){
		dp[node][j]=max(dp[node][j],gec[j]);
		if(ch(node,j+1))dp[node][j]=max(dp[node][j],dp[node][j+1]);
		cev=max(cev,dp[node][j]);
	}
}

int32_t main(){
	faster
	cin>>n>>d;
	d=min(d,n+2);
	
	FOR{
		if(i==1)continue;
		int x;cin>>x;
		x++;
		v[x].pb(i);
	}
	
	f(1);
		
	cout<<cev<<'\n';
	
	return 0;
}

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