From: "H.Yamamoto" <ocean@...2.ccsnet.ne.jp>
Date: 2004-07-11T17:21:29+09:00
Subject: Re: A little algorithmic help requested...

Hello.

>[1,2,3,4,6,7,8,11,12,15,16,17] ==> [1..4,6..8,11,12,15..17]
>
>How would *you* do this?

How about this? It seems working.

a = [1,2,3,4,6,7,8,11,12,15,16,17]
b = []

i = 0
(0..a.size).each do |j|
  if (j == a.size) || (j - i != a[j] - a[i])
    case j - i
    when 0
    when 1
      b << a[i]
    when 2
      b << a[i] << a[i+1]
    else
      b << (a[i]..a[j-1])
    end
    i = j
  end
end

p b # [1..4, 6..8, 11, 12, 15..17]