链表_leetcode445

# Definition for singly-linked list.
class ListNode(object):
    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
        """

        def getNum(head):

            cur = head
            res = []
            nums = 0

            while cur :
                res.insert(0,cur.val)
                cur = cur.next

            weight = 1
            for i in res:
                nums += i * weight
                weight = weight * 10
            return nums

        nums1 = getNum(l1)
        nums2 = getNum(l2)

        res = nums1 + nums2
        head = ListNode(0)
        p = head

        if res == 0:
            return head

        while res:
            val = res % 10

            newNode = ListNode(val)
            newNode.next = p.next
            p.next = newNode

            res = res / 10

        return head.next