Project Euler, Problem #2 in Python

As a Code Kata, I’ve been working my way through the Project Euler stuff.

Here’s the problem.

Here’s my solution:

[highlight lang=py]

1. A generator to derive the Fibonacci sequence
   def fib(): x, y = 0, 1 yield x yield y while 1: x, y = y, x+y yield y

if name == ‘main’: idx = 0 sum = 0 gen = fib()

Note: You want to be careful how you use infinite generators like the ‘fib()’ I created above.

One guy on the forums noted:

Now, replacing an odd number with O and an even with E, we get: O, O, E, O, O, E, O, O, E, O, O, E, O, O, E…And so each third number is even. We don’t need to calculate the odd numbers. Starting from an two odd terms x, y, the series is: x, y, x + y, x + 2y, 2x + 3y, 3x + 5y