Mergesort

K
w
s
L
Y 54 más contribuidores
```"""
This is a pure Python implementation of the merge sort algorithm
For doctests run following command:
python -m doctest -v merge_sort.py
or
python3 -m doctest -v merge_sort.py
For manual testing run:
python merge_sort.py
"""

def merge_sort(collection: list) -> list:
"""Pure implementation of the merge sort algorithm in Python
:param collection: some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending
Examples:
>>> merge_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> merge_sort([])
[]
>>> merge_sort([-2, -5, -45])
[-45, -5, -2]
"""

def merge(left: list, right: list) -> list:
"""merge left and right
:param left: left collection
:param right: right collection
:return: merge result
"""

def _merge():
while left and right:
yield (left if left[0] <= right[0] else right).pop(0)
yield from left
yield from right

return list(_merge())

if len(collection) <= 1:
return collection
mid = len(collection) // 2
return merge(merge_sort(collection[:mid]), merge_sort(collection[mid:]))

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(*merge_sort(unsorted), sep=",")
```

Declaración de problema

Dada una matriz de n elementos, escriba una función para ordenar la matriz

Enfoque

• Encontrar un punto medio y dividir la matriz en mitades basadas en el punto medio
• Llamar recursivamente a la función de ordenación de fusión para las dos mitades

`O(n log n)`

`O(n)`

Ejemplo

``````arr = [1, 3, 9, 5, 0, 2]

Divida la matriz en dos mitades [1, 3, 9] y [5, 0, 2]