Python Program for Cocktail Sort

In this article, we will learn about the solution to the problem statement given below.

Problem statement − We are given a list, we need to perform a bitonic sort on the given list and display the list

Cocktail Sort − Here sort takes place like bubble sort where iteration takes place in both directions.


Firstly array is traversed from left to right. During traversal, adjacent items are compared and based on the conditions, the values are swapped. By this, the largest number will be at the end of the array.

Now the array is traversed in the opposite direction and based on the conditions, elements are swapped. By this, the smallest number will be at the start.

Now let’s observe the solution in the implementation below −


 Live Demo

# function
def cocktailSort(a):
   n = len(a)
   flag = True
   start = 0
   end = n-1
   while (flag==True):
      # to ignore the result of the previous iteration
      flag = False
      # left to right traversal
      for i in range (start, end):
         if (a[i] > a[i+1]) :
            a[i], a[i+1]= a[i+1], a[i]
      # if no swap takes place array remains sorted
      if (flag==False):
      # otherwise, reset the flag
      flag = False
      # last item is aldready sorted
      end = end-1
      # iteration from right to left
      for i in range(end-1, start-1,-1):
         if (a[i] > a[i+1]):
            a[i], a[i+1] = a[i+1], a[i]
            flag = True
      # first element is already sorted
      start = start+1
# main
a = [2,5,4,3,8,3,4,6]
print("Sorted array is:")
for i in range(len(a)):
   print (a[i],end=" ")


Sorted array is:
2 3 3 4 4 5 6 8

All the variables are declared in the local scope and their references are seen in the figure above.


In this article, we have learned about how we can make a Python Program for Cocktail Sort

Updated on: 20-Dec-2019


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