From: w_a_x_man <w_a_x_man@...>
Date: 2010-11-05T03:10:14+09:00
Subject: Re: Regular Expression

On Nov 3, 10:42 am, w_a_x_man <w_a_x_...@yahoo.com> wrote:
>
> "We don't need no stinkin' loops!"
>
> def check input
>   return false  unless /\A[A-D]{0,4}\z/ =~ input
>   %w(A B C D).map{|s| input.count s}.zip( [1,1,1,2] ).
>     map{|a,b| b-a}.all?{|n| n >= 0}
> end

def check input
  /\A[A-D]{0,4}\z/.match input   and
  %w(A B C D).map{|s| input.count s}.zip( [1,1,1,2] ).
    map{|a,b| b-a}.min >= 0
end