mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
102 lines
3.0 KiB
Python
102 lines
3.0 KiB
Python
def quick_sort_3partition(sorting: list, left: int, right: int) -> None:
|
|
if right <= left:
|
|
return
|
|
a = i = left
|
|
b = right
|
|
pivot = sorting[left]
|
|
while i <= b:
|
|
if sorting[i] < pivot:
|
|
sorting[a], sorting[i] = sorting[i], sorting[a]
|
|
a += 1
|
|
i += 1
|
|
elif sorting[i] > pivot:
|
|
sorting[b], sorting[i] = sorting[i], sorting[b]
|
|
b -= 1
|
|
else:
|
|
i += 1
|
|
quick_sort_3partition(sorting, left, a - 1)
|
|
quick_sort_3partition(sorting, b + 1, right)
|
|
|
|
|
|
def quick_sort_lomuto_partition(sorting: list, left: int, right: int) -> None:
|
|
"""
|
|
A pure Python implementation of quick sort algorithm(in-place)
|
|
with Lomuto partition scheme:
|
|
https://en.wikipedia.org/wiki/Quicksort#Lomuto_partition_scheme
|
|
|
|
:param sorting: sort list
|
|
:param left: left endpoint of sorting
|
|
:param right: right endpoint of sorting
|
|
:return: None
|
|
|
|
Examples:
|
|
>>> nums1 = [0, 5, 3, 1, 2]
|
|
>>> quick_sort_lomuto_partition(nums1, 0, 4)
|
|
>>> nums1
|
|
[0, 1, 2, 3, 5]
|
|
>>> nums2 = []
|
|
>>> quick_sort_lomuto_partition(nums2, 0, 0)
|
|
>>> nums2
|
|
[]
|
|
>>> nums3 = [-2, 5, 0, -4]
|
|
>>> quick_sort_lomuto_partition(nums3, 0, 3)
|
|
>>> nums3
|
|
[-4, -2, 0, 5]
|
|
"""
|
|
if left < right:
|
|
pivot_index = lomuto_partition(sorting, left, right)
|
|
quick_sort_lomuto_partition(sorting, left, pivot_index - 1)
|
|
quick_sort_lomuto_partition(sorting, pivot_index + 1, right)
|
|
|
|
|
|
def lomuto_partition(sorting: list, left: int, right: int) -> int:
|
|
"""
|
|
Example:
|
|
>>> lomuto_partition([1,5,7,6], 0, 3)
|
|
2
|
|
"""
|
|
pivot = sorting[right]
|
|
store_index = left
|
|
for i in range(left, right):
|
|
if sorting[i] < pivot:
|
|
sorting[store_index], sorting[i] = sorting[i], sorting[store_index]
|
|
store_index += 1
|
|
sorting[right], sorting[store_index] = sorting[store_index], sorting[right]
|
|
return store_index
|
|
|
|
|
|
def three_way_radix_quicksort(sorting: list) -> list:
|
|
"""
|
|
Three-way radix quicksort:
|
|
https://en.wikipedia.org/wiki/Quicksort#Three-way_radix_quicksort
|
|
First divide the list into three parts.
|
|
Then recursively sort the "less than" and "greater than" partitions.
|
|
|
|
>>> three_way_radix_quicksort([])
|
|
[]
|
|
>>> three_way_radix_quicksort([1])
|
|
[1]
|
|
>>> three_way_radix_quicksort([-5, -2, 1, -2, 0, 1])
|
|
[-5, -2, -2, 0, 1, 1]
|
|
>>> three_way_radix_quicksort([1, 2, 5, 1, 2, 0, 0, 5, 2, -1])
|
|
[-1, 0, 0, 1, 1, 2, 2, 2, 5, 5]
|
|
"""
|
|
if len(sorting) <= 1:
|
|
return sorting
|
|
return (
|
|
three_way_radix_quicksort([i for i in sorting if i < sorting[0]])
|
|
+ [i for i in sorting if i == sorting[0]]
|
|
+ three_way_radix_quicksort([i for i in sorting if i > sorting[0]])
|
|
)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod(verbose=True)
|
|
|
|
user_input = input("Enter numbers separated by a comma:\n").strip()
|
|
unsorted = [int(item) for item in user_input.split(",")]
|
|
quick_sort_3partition(unsorted, 0, len(unsorted) - 1)
|
|
print(unsorted)
|