Python/sorts/cycle_sort.py

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"""
Code contributed by Honey Sharma
Source: https://en.wikipedia.org/wiki/Cycle_sort
"""
def cycle_sort(array: list) -> list:
"""
>>> cycle_sort([4, 3, 2, 1])
[1, 2, 3, 4]
>>> cycle_sort([-4, 20, 0, -50, 100, -1])
[-50, -4, -1, 0, 20, 100]
>>> cycle_sort([-.1, -.2, 1.3, -.8])
[-0.8, -0.2, -0.1, 1.3]
>>> cycle_sort([])
[]
"""
array_len = len(array)
for cycle_start in range(array_len - 1):
item = array[cycle_start]
pos = cycle_start
for i in range(cycle_start + 1, array_len):
if array[i] < item:
pos += 1
if pos == cycle_start:
continue
while item == array[pos]:
pos += 1
array[pos], item = item, array[pos]
while pos != cycle_start:
pos = cycle_start
for i in range(cycle_start + 1, array_len):
if array[i] < item:
pos += 1
while item == array[pos]:
pos += 1
array[pos], item = item, array[pos]
return array
2019-10-05 05:14:13 +00:00
if __name__ == "__main__":
assert cycle_sort([4, 5, 3, 2, 1]) == [1, 2, 3, 4, 5]
assert cycle_sort([0, 1, -10, 15, 2, -2]) == [-10, -2, 0, 1, 2, 15]