Python: Sort a list of elements using Cocktail shaker sort

Last update on April 23 2025 12:56:55 (UTC/GMT +8 hours)

14. Cocktail Shaker Sort

Write a Python program to sort a list of elements using Cocktail shaker sort.
From Wikipedia, Cocktail shaker sort,[1] also known as bidirectional bubble sort,[2] cocktail sort, shaker sort (which can also refer to a variant of selection sort), ripple sort, shuffle sort,[3] or shuttle sort, is a variation of bubble sort that is both a stable sorting algorithm and a comparison sort. The algorithm differs from a bubble sort in that it sorts in both directions on each pass through the list. This sorting algorithm is only marginally more difficult to implement than a bubble sort, and solves the problem of turtles in bubble sorts. It provides only marginal performance improvements, and does not improve asymptotic performance; like the bubble sort, it is not of practical interest (insertion sort is preferred for simple sorts), though it finds some use in education.

Visualization of shaker sort:

Sample Solution:

Python Code:

def cocktail_shaker_sort(nums):
    for i in range(len(nums)-1, 0, -1):
        is_swapped = False
        
        for j in range(i, 0, -1):
            if nums[j] < nums[j-1]:
                nums[j], nums[j-1] = nums[j-1], nums[j]
                is_swapped = True

        for j in range(i):
            if nums[j] > nums[j+1]:
                nums[j], nums[j+1] = nums[j+1], nums[j]
                is_swapped = True
        
        if not is_swapped:
            return nums
 
num1 = input('Input comma separated numbers:\n').strip()
nums = [int(item) for item in num1.split(',')]
print(cocktail_shaker_sort(nums))

Sample Output:

Input comma separated numbers:
 15, 37, 69, 26, 78 
[15, 26, 37, 69, 78]

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to implement cocktail shaker sort and print the list after each bidirectional pass.
Write a Python script to apply cocktail shaker sort to sort a list of numbers and count the total number of comparisons.
Write a Python program to modify cocktail shaker sort to sort a list of tuples based on a specified element.
Write a Python function to implement cocktail shaker sort and then compare its performance with bubble sort on the same dataset.

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