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 n,dat[2000004],K,n_=1;
void upd(int id,int x){
	while(1){
		dat[id]=max(dat[id],x);
		if(id==0)break;
		id=(id-1)/2;
	}
}
int got(int l,int r,int id,int a,int b){
	if(r<a||b<l)return 0;
	if(a<=l&&r<=b)return dat[id];
	return max(got(l,(l+r)/2,id*2+1,a,b),got((l+r)/2+1,r,id*2+2,a,b));
}
int main(){
	cin>>n>>K;
	while(n_<n)n_<<=1;
	for(int i=0;i<n;i++){
		int x;cin>>x;
		int cur=got(1,n_,0,x-K,x+K)+1;
		upd(x+n_-1,cur);
	}
	cout<<got(1,n_,0,-1114514,1114514);
}