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860d4f547b
* Create merge_two_lists.py that implements merging of two sorted linked lists
* Update merge_two_lists.py
Fixed formatting errors
* Fixed trailing whitespace
* Change name of function to def __str__()
* updating DIRECTORY.md
* Imported classes from singly_linked_list.py
* Update merge_two_lists.py
* Update merge_two_lists.py
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
84 lines
2.2 KiB
Python
84 lines
2.2 KiB
Python
"""
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Algorithm that merges two sorted linked lists into one sorted linked list.
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"""
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from __future__ import annotations
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from collections.abc import Iterable, Iterator
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from dataclasses import dataclass
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from typing import Optional
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test_data_odd = (3, 9, -11, 0, 7, 5, 1, -1)
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test_data_even = (4, 6, 2, 0, 8, 10, 3, -2)
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@dataclass
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class Node:
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data: int
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next: Optional[Node]
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class SortedLinkedList:
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def __init__(self, ints: Iterable[int]) -> None:
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self.head: Optional[Node] = None
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for i in reversed(sorted(ints)):
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self.head = Node(i, self.head)
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def __iter__(self) -> Iterator[int]:
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"""
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>>> tuple(SortedLinkedList(test_data_odd)) == tuple(sorted(test_data_odd))
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True
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>>> tuple(SortedLinkedList(test_data_even)) == tuple(sorted(test_data_even))
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True
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"""
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node = self.head
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while node:
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yield node.data
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node = node.next
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def __len__(self) -> int:
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"""
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>>> for i in range(3):
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... len(SortedLinkedList(range(i))) == i
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True
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True
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True
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>>> len(SortedLinkedList(test_data_odd))
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8
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"""
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return len(tuple(iter(self)))
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def __str__(self) -> str:
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"""
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>>> str(SortedLinkedList([]))
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''
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>>> str(SortedLinkedList(test_data_odd))
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'-11 -> -1 -> 0 -> 1 -> 3 -> 5 -> 7 -> 9'
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>>> str(SortedLinkedList(test_data_even))
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'-2 -> 0 -> 2 -> 3 -> 4 -> 6 -> 8 -> 10'
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"""
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return " -> ".join([str(node) for node in self])
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def merge_lists(
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sll_one: SortedLinkedList, sll_two: SortedLinkedList
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) -> SortedLinkedList:
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"""
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>>> SSL = SortedLinkedList
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>>> merged = merge_lists(SSL(test_data_odd), SSL(test_data_even))
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>>> len(merged)
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16
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>>> str(merged)
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'-11 -> -2 -> -1 -> 0 -> 0 -> 1 -> 2 -> 3 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9 -> 10'
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>>> list(merged) == list(sorted(test_data_odd + test_data_even))
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True
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"""
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return SortedLinkedList(list(sll_one) + list(sll_two))
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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SSL = SortedLinkedList
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print(merge_lists(SSL(test_data_odd), SSL(test_data_even)))
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