Introduction

Cocktail sort is the extend version of bubble sort algorithm. The elements are bubbled from both the side alternatively.

Program

def sort(array, length):
    is_swapped = True
    first = 0
    last = length - 1
    while (is_swapped == True):
        is_swapped = False
        for i in range(first, last):
            if (array[i] > array[i+1]):
                array[i], array[i+1] = array[i+1], array[i]
                is_swapped = True
        if(is_swapped == False):
            last = last-1
        for i in range(last-1, first-1, -1):
            if(array[i] > array[i+1]):
                array[i], array[i+1] = array[i+1], array[i]
                is_swapped = True
        first = first+1
       
ip_arr = [54, 26, 81, 1]
sort(ip_arr, len(ip_arr))
print("The sorted array is ")
for i in range(0, len(ip_arr)):
    print(ip_arr[i])

Output

Explanation

The steps followed in the above code are:

• In first iteration, the element from the left side is compared to each adjacent elements and swapped if required.
• In second iteration, the element from right side just before the recently swapped element is taken and compared to each element to its right and swapped if required.
• In the end the array is sorted and returned.