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insertion_sort.py
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insertion_sort.py
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from binary_search import bisect_right
def insert_with_linear_search(array, left_index, right_index):
"""
Use linear search to find a position in already sorted array[left_index...right_index-1] to insert array[right_index] into,
making array[left_index...right_index] a sorted array.
:param array:
:param left_index:
:param right_index: right_index > 0
:return:
"""
key = array[right_index]
i = right_index - 1
while i >= left_index and key < array[i]:
array[i + 1] = array[i]
i = i - 1
array[i + 1] = key
def insert_with_binary_search(array, left_index, right_index):
"""
Use binary search to find a position in already sorted array[left_index...right_index-1] to insert array[right_index] into,
making array[left_index...right_index] a sorted array.
:param array:
:param left_index:
:param right_index: right_index > 0
:return:
"""
x = array[right_index]
index = bisect_right(array, x, left_index, right_index)
array[index + 1: right_index + 1] = array[index: right_index]
array[index] = x
def insertion_sort(array, left=0, right=None, insert_method=insert_with_linear_search):
"""
inplace sort O(n ^ 2) sort
:param array:
:param left:
:param right:
:param insert_method:
:return:
"""
if right is None:
right = len(array) - 1
for j in range(left, right + 1):
insert_method(array, 0, j)
def _insertion_sort_recursive(array, length, insert_method):
if length > 1:
_insertion_sort_recursive(array, length - 1, insert_method)
insert_method(array, 0, length - 1)
def insertion_sort_recursive(array, insert_method=insert_with_linear_search):
"""
recursive version of insertion sort
:param array:
:param insert_method:
:return:
"""
_insertion_sort_recursive(array, len(array), insert_method)