diff --git a/DIRECTORY.md b/DIRECTORY.md index 2e3b4398f26e..53c53d208656 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -1267,6 +1267,7 @@ * [Comb Sort](sorts/comb_sort.py) * [Counting Sort](sorts/counting_sort.py) * [Cycle Sort](sorts/cycle_sort.py) + * [Cyclic Sort](sorts/cyclic_sort.py) * [Double Sort](sorts/double_sort.py) * [Dutch National Flag Sort](sorts/dutch_national_flag_sort.py) * [Exchange Sort](sorts/exchange_sort.py) diff --git a/sorts/cyclic_sort.py b/sorts/cyclic_sort.py new file mode 100644 index 000000000000..9e81291548d4 --- /dev/null +++ b/sorts/cyclic_sort.py @@ -0,0 +1,55 @@ +""" +This is a pure Python implementation of the Cyclic Sort algorithm. + +For doctests run following command: +python -m doctest -v cyclic_sort.py +or +python3 -m doctest -v cyclic_sort.py +For manual testing run: +python cyclic_sort.py +or +python3 cyclic_sort.py +""" + + +def cyclic_sort(nums: list[int]) -> list[int]: + """ + Sorts the input list of n integers from 1 to n in-place + using the Cyclic Sort algorithm. + + :param nums: List of n integers from 1 to n to be sorted. + :return: The same list sorted in ascending order. + + Time complexity: O(n), where n is the number of integers in the list. + + Examples: + >>> cyclic_sort([]) + [] + >>> cyclic_sort([3, 5, 2, 1, 4]) + [1, 2, 3, 4, 5] + """ + + # Perform cyclic sort + index = 0 + while index < len(nums): + # Calculate the correct index for the current element + correct_index = nums[index] - 1 + # If the current element is not at its correct position, + # swap it with the element at its correct index + if index != correct_index: + nums[index], nums[correct_index] = nums[correct_index], nums[index] + else: + # If the current element is already in its correct position, + # move to the next element + index += 1 + + return nums + + +if __name__ == "__main__": + import doctest + + doctest.testmod() + user_input = input("Enter numbers separated by a comma:\n").strip() + unsorted = [int(item) for item in user_input.split(",")] + print(*cyclic_sort(unsorted), sep=",")