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heap_sort.py
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78 lines (61 loc) · 1.68 KB
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"""
Author: OMKAR PATHAK
Created On: 31st July 2017
- Best O(nlog(n))
- Average O(nlog(n))
- Worst O(nlog(n))
"""
import inspect
def sort(_list):
"""
heap sort algorithm
:param _list: list of values to sort
:return: sorted values
"""
# TODO: Add description of how this works!
# create the heap
heapify(_list)
end = len(_list) - 1
while end > 0:
_list[end], _list[0] = _list[0], _list[end]
shift_down(_list, 0, end - 1)
end -= 1
return _list
def heapify(_list):
"""
function helps to maintain the heap property
:param _list: list of values to sort
:return: sorted values
"""
start = len(_list) // 2
while start >= 0:
shift_down(_list, start, len(_list) - 1)
start -= 1
def shift_down(_list, start, end):
root = start
while root * 2 + 1 <= end:
child = root * 2 + 1
# right child exists and is greater than left child
if child + 1 <= end and _list[child] < _list[child + 1]:
child += 1
# if child is greater than root(parent), then swap their positions
if child <= end and _list[root] < _list[child]:
_list[root], _list[child] = _list[child], _list[root]
root = child
else:
return
# 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():
"""
easily retrieve the source code
of the sort function
:return: source code
"""
return inspect.getsource(sort)