Python

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

Here’s the problem.

Here’s my solution:

	
# 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()

    while idx <= 4000000:
        idx = gen.next()
        if (g % 2 == 0): h = h+g
    print h

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