#P1156C. Match Points
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ID: 4743
Type: RemoteJudge
2000ms
256MiB
Tried: 0
Accepted: 0
Difficulty: (None)
Uploaded By:
Hydro
Tags> Match Points
No submission language available for this problem.
Description
You are given a set of points $x_1$, $x_2$, ..., $x_n$ on the number line.
Two points $i$ and $j$ can be matched with each other if the following conditions hold:
- neither $i$ nor $j$ is matched with any other point;
- $|x_i - x_j| \ge z$.
What is the maximum number of pairs of points you can match with each other?
The first line contains two integers $n$ and $z$ ($2 \le n \le 2 \cdot 10^5$, $1 \le z \le 10^9$) — the number of points and the constraint on the distance between matched points, respectively.
The second line contains $n$ integers $x_1$, $x_2$, ..., $x_n$ ($1 \le x_i \le 10^9$).
Print one integer — the maximum number of pairs of points you can match with each other.
Input
The first line contains two integers $n$ and $z$ ($2 \le n \le 2 \cdot 10^5$, $1 \le z \le 10^9$) — the number of points and the constraint on the distance between matched points, respectively.
The second line contains $n$ integers $x_1$, $x_2$, ..., $x_n$ ($1 \le x_i \le 10^9$).
Output
Print one integer — the maximum number of pairs of points you can match with each other.
Samples
4 2
1 3 3 7
2
5 5
10 9 5 8 7
1
Note
In the first example, you may match point $1$ with point $2$ ($|3 - 1| \ge 2$), and point $3$ with point $4$ ($|7 - 3| \ge 2$).
In the second example, you may match point $1$ with point $3$ ($|5 - 10| \ge 5$).