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"""

Author: OMKAR PATHAK

Created On: 31st July 2017

- Best = Average = Worst = O(n log(n))

"""

import inspect

def merge(a, b):

"""

Function to merge

two arrays / separated lists

:param a: Array 1

:param b: Array 2

:return: merged arrays

"""

c = []

while len(a) != 0 and len(b) != 0:

if a[0] < b[0]:

c.append(a[0])

a.remove(a[0])

else:

c.append(b[0])

b.remove(b[0])

if len(a) == 0:

c += b

else:

c += a

return c

def sort(_list):

"""

Function to sort an array

using merge sort algorithm

:param _list: list of values to sort

:return: sorted

"""

if len(_list) == 0 or len(_list) == 1:

return list(_list)

else:

middle = len(_list)//2

a = sort(_list[:middle])

b = sort(_list[middle:])

return merge(a, b)

from itertools import zip_longest

def sorti(_list, verbose=True):

"""

Function to sort an array

using merge sort algorithm, iteratively

:param _list: list of values to sort

:return: sorted

"""

# breakdown every element into its own list

series = [[i] for i in _list]

while len(series) > 1:

if verbose: print(series)

# iterator to handle two at a time in the zip_longest below

isl = iter(series)

series = [

merge(a, b) if b else a

for a, b in zip_longest(isl, isl)

]

return series[0]

# TODO: Are these necessary?

def time_complexities():

"""

Return information on functions

time complexity

:return: string

"""

return "Best Case: O(nlogn), Average Case: O(nlogn), Worst Case: O(nlogn)"

def get_code(iter=False):

"""

easily retrieve the source code

of the sort function

:return: source code

"""

if iter:

return inspect.getsource(sorti) + "\n"

return inspect.getsource(sort) + "\n" + inspect.getsource(merge)