From: Gavin Kistner <phrogz@...>
Date: 2011-09-04T00:36:58+09:00
Subject: Re: Beginner needing help - Writing right-angle triangle program

On Sep 3, 2011, at 7:49 AM, Patrick Lynch wrote:
> I've been going through a Haskell tutorial (Just to see what it's like)
> and saw an example program which would tell me how long each side a
> right-angle triangle is, when given the perimeter. It seemed pretty
> simple, and me, being the kind of guy that likes to write the same
> program in multiple languages, tried to write it in ruby.

Here's a simple, rather naïve approach:

def right_triangle_sides( circumference )
  [].tap do |solutions|
    1.upto(circumference-2) do |a|
      1.upto(a-1) do |b|
        c = circumference-a-b
        if a*a+b*b == c*c
          solutions.concat( [a,b,c].permutation.to_a )
        end
      end
    end
  end
end

right_triangle_sides(24).each do |sides|
  p sides
end
#=> [8, 6, 10]
#=> [8, 10, 6]
#=> [6, 8, 10]
#=> [6, 10, 8]
#=> [10, 8, 6]
#=> [10, 6, 8]