You could do that in python as well: def fib(a, b, n): return a if n == 0 else fib(b, a+b, n-1) You'll get x300 speed. The test cases are much more re

You could do that in python as well: def fib(a, b, n): return a if n == 0 else fib(b, a+b, n-1) You'll get x300 speed. The test cases are much more revealing without such constructions.