gistfile1.rb

def valid_triangle?(a, b, c)
s = (a + b + c) / 2.0
not_triangle = (s - a) * (s - b) * (s - c)

  if not_triangle <= 0
    return false
  end

  arr_s = [a,b,c].sort

  if ((arr_s[0]**2) + (arr_s[1]**2) == (arr_s[2]**2))
    return true
  elsif (a == b && b == c)
    return true
  elsif (a == b || a == c || b == c)
    return true
 else
     return false
  end
end