Szathmáry László honlapja @ DEIK

(1) memoization
from functools import lru_cache # 0, 1, 1, 2, 3, 5, 8, 13, 21, ... @lru_cache def fibo(n): assert n >= 0 if n < 2: return n else: return fibo(n - 1) + fibo(n - 2) def main(): result = fibo(44) # 701_408_733 print(result)	import std.stdio; import std.functional; // memoize uint fibo(const uint n) { if (n < 2) { return n; } else { return memoize!fibo(n - 1) + memoize!fibo(n - 2); } } void main() { int result = fibo(44); writeln(result); // 701_408_733 }

Notes:

In Python, it's enough to use a decorator on a function and we're done.
In D, memoize is a template. Use it at each recursive call within the recursive function whose results we want to cache.
memoize!fibo(n - 1) means: call fibo(n - 1) and cache its result.
It's also possible to limit the size of the cache. For that, read the docs.

memoization