Euler problem 2

gistfile1.txt

N = 4000000

# Brute force
def fib(num)
  if num < 2 
    num 
  else
    fib(num - 2) + fib(num - 1)
  end 
end

n = 0 
fib_n = 0 
sum = 0 
while fib_n < N do
  fib_n = fib(n)
  sum = sum + fib_n if (n % 3 == 0)
  n = n + 1 
end
puts "Brute force: #{sum}"

# Smarter
fib_n = 2 
sum = 0 
ratio = 1.61803399
even_ratio = ratio**3

while fib_n < N do
  sum = sum + fib_n
  fib_n = (fib_n * even_ratio).round
end
puts "Smarter: #{sum}"

Strange looking C o_O