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: Runtime Error)

# include <stdio.h>
# include <malloc.h>

int return_value(int, int);

int main(void)
{
    int N, K;
    int * list;
    int i, j;
    int count;

    scanf("%d", &N);
    list = (int *)malloc(N * sizeof(int));
    for (i=0; i<N; ++i)
        scanf("%d", list[i]);

    for (i=0; i<N; ++i)
    {
        for (j=i; j<N; ++j)
        {
            if (return_value(list[i], list[j]) <= K)
            {
                ++count;
                break;
            }
        }
        
    }
    printf("%d", count);

    return 0;
}

int return_value(int i, int j)
{
    if (i > j)
        return (i - j);
    else
        return (j - i);
}