PYTHON: Implement Functions addFirst, addLast, addBefore, addAfter

class Node: def __init__(self, value): self.value = value self.next = None self.prev = None

def getValue(self): return self.value

def getNext(self): return self.next

def setValue(self,new_value): self.value = new_value

def setNext(self,new_next): self.next = new_next

def getPrevious(self): return self.prev

def setPrevious(self,new_prev): self.prev = new_prev

def __str__(self): return ("{}".format(self.value))

__repr__ = __str__

class DoublyLinkedList: # Do NOT modify the constructor def __init__(self): self.head = None def addFirst(self, value): # write your code here def addLast(self, value): # write your code here def addBefore(self, pnode_value, value): # write your code here def addAfter(self, pnode_value, value): # write your code here

def printDLL(self): temp=self.head print(" Traversal Head to Tail") while temp: print(temp.getValue(), end=' ') last = temp temp=temp.getNext() print(" Traversal Tail to Head") while(last is not None): print(last.getValue(), end=' ') last = last.prev

def getNode(self,value): current=self.head found=False while current!=None and not found: if current.getValue()==value: found=True return current else: current=current.getNext() return