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https://github.com/TheAlgorithms/Python.git
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477b2c24b8
* chore: update print_reverse helper method Use a generator expression instead of slicing `elements_list` to improve the space and time complexity of `make_linked_list` to O(1) space and O(n) time by avoiding the creation a shallow copy of `elements_list`. * fix: add type checking and argument typing Add argument typing to all methods in `print_reverse` Add doctest to helper function `make_linked_list` and basic edge case tests to `print_reverse` * test: add `print_reverse` test Fix doctest syntax and remove edge case tests that are covered by typed arguments. Add `print_reverse` test that expects the correct values are printed out by adding a `test_print_reverse_output` helper function. * format code Co-authored-by: shellhub <shellhub.me@gmail.com>
71 lines
1.7 KiB
Python
71 lines
1.7 KiB
Python
from typing import List
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class Node:
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def __init__(self, data=None):
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self.data = data
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self.next = None
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def __repr__(self):
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"""Returns a visual representation of the node and all its following nodes."""
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string_rep = []
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temp = self
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while temp:
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string_rep.append(f"{temp.data}")
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temp = temp.next
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return "->".join(string_rep)
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def make_linked_list(elements_list: List):
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"""Creates a Linked List from the elements of the given sequence
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(list/tuple) and returns the head of the Linked List.
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>>> make_linked_list([])
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Traceback (most recent call last):
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...
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Exception: The Elements List is empty
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>>> make_linked_list([7])
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7
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>>> make_linked_list(['abc'])
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abc
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>>> make_linked_list([7, 25])
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7->25
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"""
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if not elements_list:
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raise Exception("The Elements List is empty")
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current = head = Node(elements_list[0])
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for i in range(1, len(elements_list)):
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current.next = Node(elements_list[i])
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current = current.next
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return head
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def print_reverse(head_node: Node) -> None:
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"""Prints the elements of the given Linked List in reverse order
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>>> print_reverse([])
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>>> linked_list = make_linked_list([69, 88, 73])
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>>> print_reverse(linked_list)
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73
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88
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69
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"""
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if head_node is not None and isinstance(head_node, Node):
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print_reverse(head_node.next)
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print(head_node.data)
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def main():
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from doctest import testmod
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testmod()
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linked_list = make_linked_list([14, 52, 14, 12, 43])
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print("Linked List:")
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print(linked_list)
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print("Elements in Reverse:")
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print_reverse(linked_list)
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if __name__ == "__main__":
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main()
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