Apex College Shifting Array Problem

shuffleClass.py

import math 
def shuffleClass(array,index):
     n = len(array)
     if type(array)==type([]):
          if array==[]:
               return []
          else:
               index = index % n
               gcd = math.gcd(index,n)
               for i in range(gcd):
                    temp = array[i]
                    cur = i
                    prev = i - index
                    while prev!=i:
                         prev = prev%n
                         array[cur] = array[prev]

                         cur = prev
                         prev = cur - index
                    array[cur] = temp
               print(array)
     else:
          return []
     
shuffleClass([1,2,3,4,5,6],2)
shuffleClass([1,2,3,4,5,6],-2)

Hello @jai-dewani, this seems like your first time of participating in Week 6 of #AlgorithmFridays. Thanks for being a part of it.

This is a really decent attempt at a solution for Apex College, and your solution passes most of the test cases. However, there is only one test case that it didn't pass:

• When array has a None value, your solution breaks on line 3. This is because in coding up your solution, you made an assumption that array cannot have a None value. Ideally, you want to write robust code that includes validation for invalid/unexpected input types without throwing any runtime errors.

I understand that this solution was made with a lot of assumptions of how certain things should be implemented but I think it's always best to check in with your interviewer before making assumptions on how edge cases should be implemented. I wrote about that in this article, you might find it helpful.

Apart from that, this was good! Please let me know your thoughts.

Thanks a lot @meekg33k for that detailed review, Yes I can see how line 3 will break the code, I overlooked that part even though I have an if statement checking if the input in array or not. I think just shifting line 3 to inside of that if statement should solve this problem