# Implement a linked list class Node: def __init__(self, value): self.value = value self.next = None class LinkedList: def __init__(self, value): self.head = Node(value) self.tail = self.head self.length = 1 def append(self, value): node = Node(value) self.tail.next = self.node self.tail = node self.length += 1 return self.head def prepend(self, value): node = Node(value) node.next = self.head self.head = node self.length += 1 return self.head def printList(self): array = [] currentNode = self.head while currentNode: array.append(currentNode.value) currentNode = currentNode.next return array def insert(index, value): if index == 0: return self.prepend(value) elif index >= self.length: return self.append(value) node = Node(value) currentNode = self.head.next prevNode = self.head count = 1 while currentNode: if index == count: prevNode.next = node node.next = currentNode self.length += 1 break prevNode = currentNode currentNode = currentNode.next count += 1 return self.printList() def remove(index): if index == 0: self.head = self.head.next self.head.prev = None self.length -= 1 return self.printList() currentNode = self.head.next prevNode = self.head count = 1 while currentNode: if index == count: prevNode.next = currentNode.next self.length -= 1 break prevNode = currentNode currentNode = currentNode.next count += 1 return self.printList() def reverse(self): currentNode = self.head prevNode = None self.tail = self.head while currentNode: temp = currentNode currentNode = currentNode.next temp.next = prevNode prevNode = temp self.head = temp return self.printList() class Node: def __init__(self, value): self.value = value self.prev = None self.next = None class DoublyLinkedList: def __init__(self, value): self.head = Node(value) self.tail = self.head self.length = 1 def append(self, value): node = Node(value) self.tail.next = node node.prev = self.tail self.tail = node self.length += 1 return self.head def prepend(self, value): node = Node(value) node.next = self.head node.prev = None self.head = node self.length += 1 return self.head def printList(self): array = [] currentNode = self.head while currentNode: array.append(currentNode.value) currentNode = currentNode.next return array def insert(index, value): if index == 0: return self.prepend(value) elif index >= self.length: return self.append(value) node = Node(value) currentNode = self.head.next prevNode = self.head count = 1 while currentNode: if index == count: prevNode.next = node node.prev = prevNode node.next = currentNode currentNode.prev = node self.length += 1 break prevNode = currentNode currentNode = currentNode.next count += 1 return self.printList() def remove(index): if index == 0: self.head = self.head.next self.length -= 1 return self.printList() currentNode = self.head.next prevNode = self.head count = 1 while currentNode: if index == count: prevNode.next = currentNode.next currentNode.next.prev = prevNode self.length -= 1 return self.printList() prevNode = currentNode currentNode = currentNode.next count += 1 return self.printList()