Python/sorts/double_sort.py

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def double_sort(lst):
"""this sorting algorithm sorts an array using the principle of bubble sort ,
but does it both from left to right and right to left ,
hence i decided to call it "double sort"
:param collection: mutable ordered sequence of elements
:return: the same collection in ascending order
Examples:
>>> double_sort([-1 ,-2 ,-3 ,-4 ,-5 ,-6 ,-7])
[-7, -6, -5, -4, -3, -2, -1]
>>> double_sort([])
[]
>>> double_sort([-1 ,-2 ,-3 ,-4 ,-5 ,-6])
[-6, -5, -4, -3, -2, -1]
>>> double_sort([-3, 10, 16, -42, 29]) == sorted([-3, 10, 16, -42, 29])
True
"""
no_of_elements=len(lst)
for i in range(0,int(((no_of_elements-1)/2)+1)): # we dont need to traverse to end of list as
for j in range(0,no_of_elements-1):
if (lst[j+1]<lst[j]): # applying bubble sort algorithm from left to right (or forwards)
temp=lst[j+1]
lst[j+1]=lst[j]
lst[j]=temp
if (lst[no_of_elements-1-j]<lst[no_of_elements-2-j]): # applying bubble sort algorithm from right to left (or backwards)
temp=lst[no_of_elements-1-j]
lst[no_of_elements-1-j]=lst[no_of_elements-2-j]
lst[no_of_elements-2-j]=temp
return lst
if __name__ == "__main__":
print("enter the list to be sorted")
lst = [int(x) for x in input().split()] # inputing elements of the list in one line
sorted_lst=double_sort(lst)
print("the sorted list is")
print(sorted_lst)