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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
int A[300010];
int dp[300010];

int main() {
  int N,K;
  cin>>N>>K;
  for(int i=0;i<N;i++){
    cin>>A[i];
  }
  int maxcnt=0;
  int cnt=0;
  int temp=0;
  for(int i=0;i<N;i++){
    cnt=1;
    if(dp[i]==1){
      break;
    }
    temp=A[i];
    for(int j=i;j<N-1;j++){
      if(abs(temp-A[j+1])<=K){
        cnt++;
        dp[j+1]=1;
        temp=A[j+1];
      }
      //cout<<i<<" "<<cnt<<" "<<A[j]<<endl;
    }
    //cout<<cnt<<" "<<i<<endl;
    maxcnt=max(maxcnt,cnt);
  }
  cout<<maxcnt<<endl;
  return 0;
}