LeetCode 2.两数相加

题目链接在这里：2. 两数相加 - 力扣（LeetCode）

这道题学了一些python类和子函数的语法，发现语法与C++有异曲同工之妙

class ListNode:
    def __init__(self, val=0, next=None) -> None:
        self.val = val
        self.next = next

class Solution:
    def addTwoNumbers(self, l1:ListNode, l2:ListNode) -> ListNode:
        head = tree = ListNode()
        val = tmp = 0
        while tmp or l1 or l2:
            val=tmp
            if (l1):
                val+=l1.val
                l1=l1.next
            if (l2):
                val+=l2.val
                l2=l2.next
            tmp = val // 10
            val%=10
            tree.next = ListNode(val)
            tree=tree.next
        return head.next