Bağlı Liste (Linked List)

from __future__ import annotations

from dataclasses import dataclass


@dataclass
class Node:
    value: int
    next: Node | None = None


class LinkedList:
    def __init__(self) -> None:
        self.head: Node | None = None

    def push_front(self, value: int) -> None:
        # O(1): the new node simply points at the old head.
        self.head = Node(value, self.head)

    def push_back(self, value: int) -> None:
        # O(n): walk to the last node (a tail pointer would make this O(1)).
        node = Node(value)
        if self.head is None:
            self.head = node
            return
        cur = self.head
        while cur.next is not None:
            cur = cur.next
        cur.next = node

    def index_of(self, value: int) -> int:
        cur, i = self.head, 0
        while cur is not None:
            if cur.value == value:
                return i
            cur, i = cur.next, i + 1
        return -1

    def remove(self, value: int) -> None:
        # Unlinks the first node with this value: the previous node skips over it.
        if self.head is None:
            return
        if self.head.value == value:
            self.head = self.head.next
            return
        prev = self.head
        while prev.next is not None and prev.next.value != value:
            prev = prev.next
        if prev.next is not None:
            prev.next = prev.next.next

    def __str__(self) -> str:
        values, cur = [], self.head
        while cur is not None:
            values.append(str(cur.value))
            cur = cur.next
        return " ".join(values)


items = LinkedList()
items.push_front(2)
items.push_front(1)
items.push_back(3)
print(items)               # 1 2 3
print(items.index_of(2))   # 1
items.remove(2)
print(items)               # 1 3