Problem:
Score : 400 points

Problem Statement

You are given a sequence A_1, A_2, ..., A_N and an integer K.

Print the maximum possible length of a sequence B that satisfies the following conditions:

B is a (not necessarily continuous) subsequence of A.

For each pair of adjacents elements of B, the absolute difference of the elements is at most K.

Constraints

1 \leq N \leq 300,000

0 \leq A_i \leq 300,000

0 \leq K \leq 300,000

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N K
A_1
A_2
:
A_N

Output

Print the answer.

Sample Input 1

10 3
1
5
4
3
8
6
9
7
2
4

Sample Output 1

7

For example, B = (1, 4, 3, 6, 9, 7, 4) satisfies the conditions.

It is a subsequence of A = (1, 5, 4, 3, 8, 6, 9, 7, 2, 4).

All of the absolute differences between two adjacent elements (|1-4|, |4-3|, |3-6|, |6-9|, |9-7|, |7-4|) are at most K = 3.

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
using System.Threading;
using System.Runtime.CompilerServices;
static class Program{
	const int mod=(int)1e9+7;
	static void Main(){
		Sc sc=new Sc();
		var s=sc.Ia;
		int m=300000;
		long ans=0;
		St st=new St(m+1,true,true,0);
		for(int i = 0;i<s[0];i++) {
			var e=sc.I;
			var d=st.Get(Max(e-s[1],0),Min(e+s[1],m));
			st.Ud(e,d.d+1);
			ans=Max(ans,d.d+1);
		}
		Console.WriteLine("{0}",ans);
	}
}
public class St{
	public class Dt{
		public int n;
		public long d;
		public Dt(long d,int n){this.d=d;this.n=n;}
		public override string ToString()=>"n:"+n.ToString()+" d:"+d.ToString();
	}
	private Dt[] dat;
	private int n,cnt;
	private bool ku;
	private Dt du;
	private Func<Dt,Dt,Dt> compare;
	public St(int n,bool mm,bool ku,long df){
		this.n=n;
		this.ku=ku;
		if(mm){du=new Dt(long.MinValue,-1);compare=CoMax;}
		else{du=new Dt(long.MaxValue,-1);compare=CoMin;}
		cnt=n<<1;
		dat=new Dt[cnt];
		for(int i = cnt-1;i>=cnt-n;i--) {dat[i]=new Dt(df,n-cnt+i);}
		for(int i = cnt-n-1;i>0;i--) {dat[i]=dat[i<<1];}
	}
	private Dt CoMax(Dt x,Dt y){return x.d>y.d?x:y;}
	private Dt CoMin(Dt x,Dt y){return x.d<y.d?x:y;}
	public void Ud(int q,long b){
		q+=n;
		if(ku){dat[q].d+=b;}
		else{dat[q].d=b;}
		while(q>1){dat[q>>=1]=compare(dat[q<<1],dat[(q<<1)+1]);}
	}
	public Dt Get(int l,int r){
		Dt x=du;
		l+=n;r+=n;
		while(l<=r){
			if((l&1)==1){x=compare(x,dat[l++]);}
			if((r&1)==0){x=compare(x,dat[r--]);}
			l>>=1;r>>=1;
		}
		return x;
	}
}
public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}