#0227

Memoized Fibonacci

MediumPython25 min20 XP

Problem

Return the nth Fibonacci number where fib(0)=0 and fib(1)=1. Use memoization.

Why This Matters

Memoization is the simplest bridge from recursion to dynamic programming.

Function Signature

def fib(n):

Examples

Example 1

Inputn = 8

Output21

The sequence is 0, 1, 1, 2, 3, 5, 8, 13, 21.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Prefer readable Python before micro-optimizing.

CodePython

def fib(n):
    """
    Input example: n = 8
    Return: 21
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

def fib(n):
    """
    Input example: n = 8
    Return: 21
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Inputn = 8

Expected21

The sequence is 0, 1, 1, 2, 3, 5, 8, 13, 21.

Hidden Test Categories

n = 0n = 1larger n such as 30