CSES - Apartments
  • Time limit: 1.00 s
  • Memory limit: 512 MB
There are $n$ applicants and $m$ free apartments. Your task is to distribute the apartments so that as many applicants as possible will get an apartment.

Each applicant has a desired apartment size, and they will accept any apartment whose size is close enough to the desired size.


The first input line has three integers $n$, $m$, and $k$: the number of applicants, the number of apartments, and the maximum allowed difference.

The next line contains $n$ integers $a_1, a_2, \ldots, a_n$: the desired apartment size of each applicant. If the desired size of an applicant is $x$, he or she will accept any apartment whose size is between $x-k$ and $x+k$.

The last line contains $m$ integers $b_1, b_2, \ldots, b_m$: the size of each apartment.


Print one integer: the number of applicants who will get an apartment.

  • $1 \le n, m \le 2 \cdot 10^5$
  • $0 \le k \le 10^9$
  • $1 \le a_i, b_i \le 10^9$

4 3 5
60 45 80 60
30 60 75