Level 5Exercise #118

Memoized Fibonacci

Implement recursive Fibonacci while caching previously computed arguments.

What you’ll practice

This Level 5 exercise focuses on lru_cache in the Algorithms curriculum. Solve the challenge prompt above using clear, idiomatic Python and the relevant language or standard-library tools.

Relevant Python reference: Python Standard Library — Algorithms.

Sample Test Cases

Example #1

Input:fibonacci(n=35)

Output:9227465

Reference Solution

Reveal Reference Solution

def fibonacci(n: int) -> int:
    from functools import lru_cache
    @lru_cache(maxsize=None)
    def fib(k):
        return k if k < 2 else fib(k-1) + fib(k-2)
    return fib(n)

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Memoized Fibonacci

What you’ll practice

Sample Test Cases

Further Reading

Reference Solution