Python Coding challenge - Day 428| What is the output of the following Python Code?

 

Code Explanation:

1. Import lru_cache

from functools import lru_cache

lru_cache stands for Least Recently Used cache.

It's a decorator that caches the results of function calls so repeated inputs don't recompute.

2. Define Fibonacci Function with Memoization

@lru_cache()

def fib(n):

    return n if n < 2 else fib(n - 1) + fib(n - 2)

This is a recursive function for computing Fibonacci numbers.

Base case: If n is 0 or 1, return n directly.

Recursive case: Add the previous two Fibonacci numbers:

F(n)=F(n−1)+F(n−2)

@lru_cache() stores the result of each call so fib(5) doesn’t recalculate fib(4) and fib(3) again — this drastically improves performance!

3. Compute fib(10)

print(fib(10))

The 10th Fibonacci number (using 0-based indexing) is:

F(0)=0F(1)=1F(2)=1F(3)=2F(4)=3F(5)=5F(6)=8F(7)=13F(8)=21F(9)=34F(10)=55

Output:

55