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.Linq;

namespace D
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] In = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int n = In[0];
            int k = In[1];
            int[] A = new int[n];
            for(int i = 0; i < n; i++)
            {
                A[i] = int.Parse(Console.ReadLine());
            }
            int ans = 0;
            for(int s=0; s < n - ans -1 ; s++)
            {
                int res = 0;
                int before_idx = s;
                for (int i = s+1 ; i < n; i++)
                {
                    if ((int)Math.Abs(A[before_idx] - A[i]) <= k)
                    {
                        res++;
                        before_idx = i;
                    }
                }
                ans = (int)Math.Max(ans, res);
            }
            Console.WriteLine(ans+1) ;
        }
    }
}