Instructions.md

instructions

Let's get started 🚀 Following these instructions you should be able to solve this exercise.

The staircase problem

In this exercise we will look at the staircase problem. This problem is often used as a coding interview question at companies such as Amazon. Shout out to CS Dojo: Recursive Staircase Problem on YouTube for the inspiration.

The staircase problem asks for the count of all possible paths up a staircase of size n given a set of possible step sizes. By default, the allowed step sizes are [1, 2].

For example, a staircase with size n = 4, i.e. 4 steps, and [1, 3, 5] as allowed step sizes, has 3 possible ways to get up. Note that the step size 5 is not used as you are not allowed to overstep the stairs.

Exercise

Your job is to implement a ways_up function that returns the amount of ways up a staircase with n steps and specified step sizes.

Implement this in the staircase.py file.

Example

Here are some example results your function should return

>>> ways_up(1)
1

>>> ways_up(5)
8

>>> ways_up(5, step_sizes=[1, 3, 5])
5

Test

To test your implementation, this exercise comes with a predefined test suite. To run this test suite, execute the staircase.test.py file in this folder with python3:

python3 staircase.test.py