└── third.py


/third.py:
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 1 | class Node:
 2 |     def __init__(self, data, nxt=None):
 3 |         self.data = data
 4 |         self.nxt = nxt
 5 | 
 6 |     def __str__(self):
 7 |         return f"[{self.data}]"
 8 | 
 9 |     def add_to_end(self, data):
10 |         n = self  # n = root
11 |         while not n.is_last():
12 |             n = n.nxt  # n == Node(30)
13 | 
14 |         n.nxt = Node(data)
15 | 
16 |     def is_last(self):
17 |         if self.nxt is None:
18 |             return True
19 |         else:
20 |             return False
21 | 
22 | 
23 | class LinkedList:
24 |     root: Node
25 | 
26 |     def __init__(self, data, _root=None):
27 |         if not _root:
28 |             self.root = Node(data)
29 | 
30 |     def add_to_end(self, data):
31 |         self.root.add_to_end(data)
32 | 
33 |     def add_to_beginning(self, data):
34 |         new_node = Node(data)
35 |         second_node = self.root
36 |         self.root = new_node
37 |         new_node.nxt = second_node
38 | 
39 |     def add_to_index(self, index, data):
40 |         new_node = Node(data)
41 |         n = self.root
42 |         for i in range(index - 1):
43 |             n = n.nxt  # [5]
44 |         old_next = n.nxt  # [10]
45 |         n.nxt = new_node  # [5] -> [7]
46 |         new_node.nxt = old_next  # [7] -> [10]
47 | 
48 |     def get_at_index(self, index):
49 | 
50 |         n = self.root
51 |         for i in range(index):
52 |             n = n.nxt
53 |         return n.data
54 | 
55 |     def __str__(self):
56 |         linked_arr = []
57 |         n = self.root
58 |         while not n.is_last():
59 |             linked_arr.append(str(n))
60 |             n = n.nxt
61 |         linked_arr.append(str(n))
62 | 
63 |         return " -> ".join(linked_arr)
64 | 
65 |     def append(self, data):
66 |         self.add_to_end(data)
67 | 
68 |     def __getitem__(self, index):
69 |         return self.get_at_index(index)
70 | 
71 |     def __setitem__(self, index, value):
72 |         self.add_to_index(index, value)
73 | 
74 |     def __iter__(self):
75 |         return self
76 | 
77 |     def __next__(self):
78 |         if self.root is None:
79 |             raise StopIteration
80 |         else:
81 |             current = self.root
82 |             self.root = self.root.nxt
83 |             return current
84 | 
85 | l = LinkedList(0)
86 | l.append(1)
87 | l.append(2)
88 | l.append(4)
89 | for el in l:
90 |     print(el)


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