Python Coding challenge - Day 544| What is the output of the following Python Code?

 

Code Explanation:

1. Function Definition

def memo_fib(n, memo={}):

memo_fib is a function to compute the nth Fibonacci number.

n: The Fibonacci number to compute.

memo={}: Default parameter, a dictionary to store previously computed results (memoization).

2. Check if Result is Already Memoized

    if n in memo:

        return memo[n]

If we've already calculated memo_fib(n) before, return the cached value directly.

This avoids redoing the computation for that n.

3. Base Case of Fibonacci Sequence

    if n <= 2:

        return 1

The first two Fibonacci numbers are defined as:

fib(1) = 1

fib(2) = 1

If n is 1 or 2, return 1.

4. Recursive Case With Memoization

    memo[n] = memo_fib(n - 1, memo) + memo_fib(n - 2, memo)

For other values of n, compute it recursively:

fib(n) = fib(n-1) + fib(n-2)

Save this result to memo[n] so it can be reused later.

5. Return the Computed Result

    return memo[n]

Return the memoized value (either just computed or already stored).

6. Call and Print the Result

print(memo_fib(6))

This calls the function to compute fib(6), which equals 8, and prints the result.

Output

8

Because the Fibonacci sequence goes:

1, 1, 2, 3, 5, 8...

So fib(6) = 8.

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