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Write a class LinkedList that holds a linked list of values. Your class should be in a source file named linked_list.py, and should support the following operations: LinkedList(list) - create a LinkedList that initially holds the values in the given Python list l.to_list() - return a Python list containing the values in this LinkedList l.len() - return the number of nodes in a LinkedList l.get(n) - return the value in the nth node, where nodes are numbered from 0. You may assume that 0 <= n < l.len(). l.has(x) - true if the list includes the value x l.delete(x) - delete the first occurrence (if any) of the value x l.rotate() - move the last node in the list to the head of the list; does nothing if the list is empty l.starts_with(m) - true if the elements of the LinkedList m appear at the beginning of l l.contains(m) - true if the elements of the LinkedList m appear in succession anywhere in l l.ends_with(m) - true if the elements of the LinkedList m appear in succession at the end of l Important: You may not use Python lists anywhere, except in the initializer and the to_list() method. Your LinkedList class may not store a Python list in any attribute. Also, generators (which we will study later in Programming 1) are not allowed in this assignment. You do not need to read any input or write any output; simply submit a file linked_list.py containing the class described above. Sample usage #1: >>> l = LinkedList([2, 7, 4, 9, 18, 19, 22]) >>> l.to_list() [2, 7, 4, 9, 18, 19, 22] >>> l.len() 7 >>> l.get(3) 9 >>> l.has(17) False >>> o = LinkedList([7]) >>> o.to_list() [7] >>> o.len() 1 >>> e = LinkedList([]) >>> e.to_list() [] >>> e.len() 0 Sample usage #2: >>> l = LinkedList([2, 7, 6, 4]) >>> l.delete(2) >>> l.delete(5) >>> l.delete(4) >>> l.to_list() [7, 6] >>> l.delete(6) >>> l.delete(7) >>> l.to_list() [] >>> l.delete(8) >>> l.to_list() []
Apa yang saya coba:
class Node: def __init__(self, value): self.value = value self.next = None class LinkedList: def __init__(self, values): self.head = None self.length = 0 # Track the length of the linked list for value in values: self.append(value) def append(self, value): new_node = Node(value) if not self.head: self.head = new_node else: current = self.head while current.next: current = current.next current.next = new_node self.length += 1 def to_list(self): result = [] current = self.head while current: result.append(current.value) current = current.next return result def len(self): return self.length def get(self, n): if n < 0 or n >= self.length: raise IndexError("Index out of range") current = self.head for _ in range(n): current = current.next return current.value def has(self, x): current = self.head while current: if current.value == x: return True current = current.next return False def delete(self, x): if not self.head: return if self.head.value == x: self.head = self.head.next self.length -= 1 return current = self.head while current.next: if current.next.value == x: current.next = current.next.next self.length -= 1 return current = current.next def rotate(self): if not self.head or not self.head.next: return current = self.head while current.next.next: current = current.next current.next.next = self.head self.head = current.next current.next = None def starts_with(self, m): current_l = self.head current_m = m.head while current_l and current_m: if current_l.value != current_m.value: return False current_l = current_l.next current_m = current_m.next return not current_m def contains(self, m): current_l = self.head while current_l: if self.starts_with_helper(current_l, m): return True current_l = current_l.next return False def starts_with_helper(self, l, m): current_l = l current_m = m.head while current_l and current_m: if current_l.value != current_m.value: return False current_l = current_l.next current_m = current_m.next return not current_m def ends_with(self, m): current_l = self.head current_m = m.head if not current_m: return True while current_l.next: current_l = current_l.next while current_m.next: current_m = current_m.next while current_l and current_m: if current_l.value != current_m.value: return False current_l = current_l.next current_m = current_m.next return not current_m
Solusi 1
Mengutip:Anda tidak boleh menggunakan daftar Python di mana pun, kecuali di penginisialisasi dan metode to_list(). Kelas LinkedList Anda tidak boleh menyimpan daftar Python di atribut apa pun. Selain itu, generator tidak diperbolehkan dalam tugas ini.
Cukup jelas: Anda tidak dapat menggunakan Daftar kecuali jika dia secara khusus mengizinkannya. Hal ini untuk memastikan bahwa Anda benar-benar membuat dan melintasi tautan alih-alih menyimpannya dalam koleksi Python dan menggunakan metode akses bawaannya.
Generator yang belum Anda pelajari – akan hadir nanti – jadi jika kode “Anda” menyertakannya karena Anda menyalin dan menempelkan contoh dari internet, Anda akan gagal dalam latihan. Jadi, jika Anda melakukan plagiat (yang sebenarnya merupakan ide buruk), Anda perlu memahami kode yang Anda curi dengan sangat detail sebelum mengirimkannya. Akan jauh lebih mudah untuk menulis kode Anda sendiri karena Anda tidak dapat menggunakan elemen yang belum Anda temui!
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