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++ (GCC 9.2.1) (judge verdict: Time Limit Exceeded)

#include<bits/stdc++.h>
using namespace std;
#define ll  long long 
#define INF 999999999
#define rep(i,n) for(int i=0;i<n;i++)
const ll MOD = 1000000007;
ll cnt =0,ans=0;
const int MAX = 510000;



int main(){

   int n,k;    cin >> n >> k;
   int a[n];
   for(int i=0;i<n;i++)cin >> a[i];
   int dp[n];
   for(int i=0;i<n;i++)dp[i] = 1;
   
   for(int i=1;i<n;i++){
       for(int j=1;i-j >=0 ;j++){
          if(abs(a[i] - a[i-j]) <=k){
              dp[i] = max (dp[i],dp[i-j] + 1);
              
          }
          else continue;
       }
   }

   cout << dp[n-1] << endl;

}