Here's my solution to Problem 2.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| """Sums all the even-valued Fibonacci numbers less than 4,000,000. | |
| For more info, see http://projecteuler.net/index.php?section=problems&id=2 | |
| """ | |
| # Taken from the Python Decorator Library | |
| class memoized(object): | |
| """Decorator that caches a function's return value each time it is called. | |
| If called later with the same arguments, the cached value is returned, and | |
| not re-evaluated. | |
| """ | |
| def __init__(self, func): | |
| self.func = func | |
| self.cache = {} | |
| def __call__(self, *args): | |
| try: | |
| return self.cache[args] | |
| except KeyError: | |
| self.cache[args] = value = self.func(*args) | |
| return value | |
| except TypeError: | |
| # uncachable -- for instance, passing a list as an argument. | |
| # Better to not cache than to blow up entirely. | |
| return self.func(*args) | |
| def __repr__(self): | |
| """Return the function's docstring.""" | |
| return self.func.__doc__ | |
| @memoized | |
| def fib(term): | |
| """Calculate the nth Fibonacci number.""" | |
| if (1 >= term): | |
| return term | |
| return fib(term - 2) + fib(term - 1) | |
| def find_highest_necessary_num(max): | |
| """Find the highest n such that fib(n) < max.""" | |
| n = 0 | |
| while(fib(n) < max): | |
| n += 1 | |
| return n | |
| def problem_two(): | |
| """Calculate the sum of the even Fibonacci numbers less than 4,000,000.""" | |
| fibs = [fib(n) for n in range(find_highest_necessary_num(4000000))] | |
| return sum([cur_fib for cur_fib in fibs if not cur_fib % 2]) | |
| if (__name__ == "__main__"): | |
| print problem_two() | |
Back to flipping out...
