2.Add Two Numbers Leetcode Python

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.


Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)

Output: 7 -> 0 -> 8

这道题要将两个linklist相加，加的时候需要用一个val来记录当前相加的值，再将得到的值添加到新的Linklist末尾。

最后当最后val还剩下1的时候还需要再添加一个新的node作为尾巴。

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    # @return a ListNode
    def addTwoNumbers(self, l1, l2):
        val=0
        dummy=head=ListNode(0)
        while l1 or l2:
            if l1:
                val+=l1.val
                l1=l1.next
            if l2:
                val+=l2.val
                l2=l2.next
            head.next=ListNode(val%10)
            head=head.next
            val/=10
        if val==1:
            head.next=ListNode(1)
        return dummy.next