class Node:
def __init__(self, item):
self.data = item
self.next = None
class LinkedList:
def __init__(self):
self.nodeCount = 0
self.head = None
self.tail = None
def __repr__(self):
if self.nodeCount == 0:
return 'LinkedList: empty'
s = ''
curr = self.head
while curr is not None:
s += repr(curr.data)
if curr.next is not None:
s += ' -> '
curr = curr.next
return s
def getAt(self, pos):
if pos < 1 or pos > self.nodeCount:
return None
i = 1
curr = self.head
while i < pos:
curr = curr.next
i += 1
return curr
def insertAt(self, pos, newNode):
if pos < 1 or pos > self.nodeCount + 1:
return False
if pos == 1:
newNode.next = self.head
self.head = newNode
else:
if pos == self.nodeCount + 1:
prev = self.tail
else:
prev = self.getAt(pos - 1)
newNode.next = prev.next
prev.next = newNode
if pos == self.nodeCount + 1:
self.tail = newNode
self.nodeCount += 1
return True
def getLength(self):
return self.nodeCount
def traverse(self):
result = []
curr = self.head
while curr is not None:
result.append(curr.data)
curr = curr.next
return result
def concat(self, L):
self.tail.next = L.head
if L.tail:
self.tail = L.tail
self.nodeCount += L.nodeCount