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 Julia (1.4.0) (judge verdict: Runtime Error)

function solve()
    N,K=parse.(Int,split(readline()))
    D=zeros(Int,N)
    for _ in 1:N
        Ai=parse(Int,readline())
        mx=0
        for i=Ai-K:Ai+K
            if 1<=i<=N
                if D[i]>mx
                    mx=D[i]
                end
            end
        end
        D[Ai]=mx+1
        #println(D)
    end
    println(maximum(D))
end
solve()