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 Java (OpenJDK 11.0.6) (judge verdict: Time Limit Exceeded)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    private static FastScanner fs = new FastScanner();
    public static void main(String[] args) {

        int n = fs.nextInt();
        int k = fs.nextInt();
        int arr[] = new int [n];
        for(int i=0;i<n;i++) arr[i] = fs.nextInt();
        int dp[] = new int [n];
        int max = Integer.MIN_VALUE;
        for(int i=1;i<n;i++) {
            for (int j = 0; j < i; j++) {
                if(Math.abs(arr[j]-arr[i])<=k)
                {
                    dp[i] = Math.max(dp[i],dp[j]+1);
                }
            }
            max = Math.max(max,dp[i]);
        }
        System.out.println(max+1);
    }



    static class FastScanner {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        String next() {
            while (!st.hasMoreTokens())
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] readArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt();
            return a;
        }

        long nextLong() {
            return Long.parseLong(next());
        }
        int  gcd(int a,int b)
        {
            while (b > 0)
            {
                int  temp = b;
                b = a % b;
                a = temp;
            }
            return a;
        }
        private int upper(int arr[],int key){
            int low = 0;
            int high = arr.length-1;
            while(low < high){
                int mid = low + (high - low+1)/2;
                if(arr[mid] <= key){
                    low = mid;
                }
                else{
                    high = mid-1;
                }
            }
            return low;
        }
        public int lower(int arr[],int key){
            int low = 0;
            int high = arr.length-1;
            while(low < high){
                int mid = low + (high - low)/2;
                if(arr[mid] >= key){
                    high = mid;
                }
                else{
                    low = mid+1;
                }
            }
            return low;
        }
    }
}