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