Python Coding challenge - Day 541| What is the output of the following Python Code?

 

Code Explanation:

Function Definition

def climb_stairs(n):

Purpose: Defines a function climb_stairs that calculates how many distinct ways there are to climb n steps.

Rule: You can climb either 1 or 2 steps at a time.

Classic Problem: This is a variation of the Fibonacci sequence.

Initialize Base Cases

    a, b = 1, 1

Purpose: Initializes two variables:

a (ways to climb to step 0): 1 way (do nothing)

b (ways to climb to step 1): 1 way (one single step)

These serve as the base of the recurrence relation:

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

Iterative Loop

    for _ in range(n-1):

Purpose: Runs the loop n - 1 times.

Why? Because we already know how to reach step 1 (b), and we need to compute up to step n.

Update Step Counts

        a, b = b, a + b

Purpose: Simulates Fibonacci calculation:

Set a to the previous b (ways to reach previous step)

Set b to a + b (total ways to reach the current step)

Example for n = 5:

Step 2: a=1, b=2

Step 3: a=2, b=3

Step 4: a=3, b=5

Step 5: a=5, b=8

Return the Result

    return b

Purpose: After the loop, b holds the total number of ways to climb n stairs.

Result for n = 5: 8 (8 distinct ways)

Function Call and Output

print(climb_stairs(5))

Purpose: Calls the function with n = 5 and prints the result.

Output: 8

Final Output:

8

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