Created
July 4, 2019 20:50
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Tail Recursion Optimizations in Python
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| class BreakOutStack(Exception): | |
| """Raised to clear stack frame and reset""" | |
| def __init__(self, *args): | |
| self.args = args | |
| def tail_recursive(fn): | |
| def _wrapped_tail_recursive(*args): | |
| while True: | |
| try: | |
| return fn(*args) | |
| except BreakOutStack as b: | |
| args = b.args | |
| return _wrapped_tail_recursive | |
| def recurse(*args): | |
| raise BreakOutStack(*args) | |
| @tail_recursive | |
| def factoral(n, a = 1): | |
| if n < 1: | |
| raise Exception("Bad Input") | |
| if n == 1: | |
| return a | |
| return recurse(n - 1, n * a) | |
| @tail_recursive | |
| def fibonnacci(n, a = 0, b = 1): | |
| if n < 0: | |
| raise Exception("Bad Input") | |
| if n == 0: | |
| return a | |
| if n == 1: | |
| return b | |
| return recurse(n - 1, b, a + b) | |
| n = 100000 | |
| fn = fibonnacci | |
| print("fn({}) => {}".format(n, fn(n))) |
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