Python Program for Gnome Sort

In this article we are going to see Gnome Sort with Python.

Algorithm Steps:

• If you are at the start of the array then go to the right element (from arr[0] to arr[1]).
• If the current array element is larger or equal to the previous array element then go one step right

                   if (arr[i] >= arr[i-1])
                      i++;

• If the current array element is smaller than the previous array element then swap these two elements and go one step backwards 

                       if (arr[i] < arr[i-1])
                       {
                           swap(arr[i], arr[i-1]);
                           i--;
                       }

• Repeat steps 2) and 3) till ‘i’ reaches the end of the array (i.e- ‘n-1’)
• If the end of the array is reached then stop and the array is sorted.

# Python program to implement Gnome Sort

# A function to sort the given list using Gnome sort
def gnomeSort(arr, n):
    index = 0
    while index < n:
        if index == 0:
            index = index + 1
        if arr[index] >= arr[index - 1]:
            index = index + 1
        else:
            arr[index], arr[index - 1] = arr[index - 1], arr[index]
            index = index - 1

    return arr

# Driver Code
arr = [34, 2, 10, -9]
n = len(arr)

arr = gnomeSort(arr, n)
print("Sorted sequence after applying Gnome Sort:", end=" ")
for i in arr:
    print(i, end=" ")

# Contributed By Harshit Agrawal

Sorted sequence after applying Gnome Sort : -9 2 10 34

Time Complexity: O(n²)

Auxiliary Space: O(1)
Please refer complete article on Gnome Sort for more details!