linkedlist.py

class Node:
 def __init__(self, data=0, next=None):
 self.data = data
 self.next = next

 def __repr__(self):
 return 'Node(%r)' % self.data

class LinkedList:
 def __init__(self, iter=()):
 self.next = None
 node = self
 for o in iter:
 node.next = node = Node(o)

 @property
 def head(self):
 return self.next

 def __bool__(self):
 return self.next is not None

 def __repr__(self):
 return 'LinkedList([%s])' % ', '.join(map(repr, self))

 def __len__(self):
 n = 0
 node = self.next
 while node:
 n += 1
 node = node.next
 return n

 def __iter__(self):
 node = self.next
 while node:
 yield node.data
 node = node.next

 def nodes(self):
 node = self.next
 while node:
 yield node
 node = node.next

 def tail(self):
 node = self
 while node.next:
 node = node.next
 return node

 def insert(self, value, node=None):
 node = node or self
 node.next = Node(value, node.next)
 return node.next

 def remove(self, node=None):
 node = node or self
 if not node.next:
 raise ValueError("can't remove past last node")
 node.next = node.next.next

 def insert_all(self, values, node=None):
 node = node or self
 for value in values:
 node = self.insert(value, node)
 return node if node is not self else None

 def remove_all(self, node1=None, node2=None):
 node1 = node1 or self
 while node1.next != node2:
 self.remove(node1)

 def find(self, value):
 node = self.next
 while node:
 if node.data == value:
 return node
 node = node.next
 return node

 def find_prev(self, value):
 node = self
 while node.next:
 if node.next.data == value:
 return node
 node = node.next
 return node if node is not self else None

 def reverse(self):
 prev = None
 node = self.next
 while node:
 next = node.next
 node.next = prev
 prev = node
 node = next
 self.next = prev
 return self


def merge(l1, l2):
 l3 = LinkedList()
 n1 = l1.next
 n2 = l2.next
 n3 = None
 while n1 or n2:
 if n1 and (not n2 or n1.data <= n2.data):
 val = n1.data
 n1 = n1.next
 else:
 val = n2.data
 n2 = n2.next
 n3 = l3.insert(val, n3)
 return l3


def add(l1, l2):
 l3 = LinkedList()
 n1 = l1.next
 n2 = l2.next
 n3 = None
 c = 0
 last = None
 while n1 or n2:
 x1 = n1.data if n1 else 0
 x2 = n2.data if n2 else 0
 c, s = divmod(x1 + x2 + c, 10)
 n3 = l3.insert(s, n3)
 if s:
 last = n3
 n1 = n1 and n1.next
 n2 = n2 and n2.next
 if c:
 l3.insert(c, n3)
 else:
 l3.remove_all(last)
 return l3