AlgorithmFriday_Week6

shuffleClass.py

def shiftLeft(arr, numm):
    for _ in range(numm):                # O(k)
        temp = arr[0]
        for i in range(len(arr)-1):      # O(n)
            arr[i] = arr[i+1]
        arr[-1] = temp
    return arr

def shiftRight(arr, numm):
    for _ in range(numm):                # O(k)
        temp = arr[-1]
        for i in range(len(arr)-1,0,-1): # O(n)
            arr[i] = arr[i-1]
        arr[0] = temp
    return arr   

def shuffleClass(array, num):
    try: 
        # Check if array None or empty
        if array == None or len(array)==0:
            return []
        # Check if num==0 or array contains only one element
        elif num ==None or num%len(array)==0 or len(array)<=1:
            return array
        else:
            # Assume we're given an array of 5 elements, 
            # Shifting right 7 times is the same as shifting right 2 times i.e. 7%5 of which the later is more optimised
            # Likewise, shifting right 4 times is the same as shifting left 1 time of which the later is more optimised
            if num<0:
                # convert to positive if negative
                num = len(array)+num
                num %= len(array)
            else:
                num %= len(array)
            # Given an array of size n, we'll only shift n/2 times at most
            if num <= len(array)//2:
                # print(f"I shift Right {num} times")
                return shiftRight(array, num)
            else:
                # print(f"I shift Left {len(array)-num} times")
                return shiftLeft(array, len(array)-num)
    except:
        return []

Hello @Julisam, thank you participating in Week 6 of #AlgorithmFridays.

You came really close to coming up with the most optimal solution for this problem with the optimization you had on line 26 - 41. That was really smart.

However, your solution didn't pass some of the test cases, more specifically the cases where num had a negative value. I think the error is traceable to line 31: num %= len(array). What do you think?

That said, you are still in the running for the $50 award if you're able to correct in on/before 3.00 pm WAT today.

Thanks once again for participating and see you later today for Week 7 of #AlgorithmFridays.

Thank you @meekg33k.
I have spotted the error and made adjustments.
My mistake was not testing my solution on all test cases when I revised the code, I only assumed its correct.