add_two_numbers.py

class ListNode:
	def __init__(self,x):
		self.val=x
		self.next=None

class Solution(object):
	def addTwoNumbers(self,l1,l2):
		"""
		:type l1:ListNode
		:type l2:ListNode
		:rtype: ListNode
		"""
		dummy = ListNode(0)
		current, carry = dummy, 0

		while l1 or l2:
			val = carry
			if l1:
				val+=l1.val
				l1=l1.next
			if l2:
				val+=l2.val
				l2=l2.next
			carry, val = val/10,val % 10
			current.next=ListNode(val)
			current=current.next
		if carry == 1:
			current.next=ListNode(1)
		return dummy.next
if __name__=='__main__':
	a,a.next,a.next.next = ListNode(2),ListNode(4),ListNode(3)
	b,b.next,b.next.next = ListNode(5),ListNode(6),ListNode(4)
	result = Solution().addTwoNumbers(a,b)
	print "{0} -> {1} ->{2}".format(result.val,result.next.val,result.next.next.val)