triangle.rb

def triangle(a, b, c)
  kolmio = [a, b, c]

  if a >= 0 || b >= 0 || c >= 0
    raise TriangleError.new('No side can be zero or negative')
  end

  if ((a >= b + c) || (b >= a + c) || (c >= a + b))
    raise TriangleError.new('No side can be equal or greater than sum of the other sides')
  end

  if kolmio.uniq.size == 1 then
  return :equilateral

  elsif kolmio.uniq.size == 2 then
  return :isosceles

  elsif kolmio.uniq.size == 3 then
  return :scalene
  end
end