【leetcode】两数相加（Add Two Numbers）【python c++】

短命女 2022-05-15 13:35 157阅读 0赞

![这里写图片描述][70]

## **python** ##

#Definition for singly-linked list.
    class ListNode:
        def __init__(self, x):
            self.val = x
            self.next = None
    
    class Solution:
        def addTwoNumbers(self, l1, l2):
            """ :type l1: ListNode :type l2: ListNode :rtype: ListNode """
            carry = 0
            l3 = ListNode(0)
            tmp1 = l1
            tmp2 = l2
            tmp3 = l3
            while tmp1 != None and tmp2 != None:
                if tmp1.val + tmp2.val + carry >= 10:
                    tmp3.val = tmp1.val + tmp2.val + carry - 10
                    carry = 1
                else:
                    tmp3.val = tmp1.val + tmp2.val + carry
                    carry = 0
                tmp1 = tmp1.next
                tmp2 = tmp2.next
                if tmp1 != None and tmp2 != None:
                    tmp3.next = ListNode(0)
                    tmp3 = tmp3.next
            if tmp1 == None and tmp2 != None:
                while tmp2!= None:
                    if tmp2.val + carry >= 10:
                        carry = 1
                        tmp3.next = ListNode(tmp2.val + carry - 10)
                    else:
                        tmp3.next = ListNode(tmp2.val + carry)
                        carry = 0
                    tmp3 = tmp3.next
                    tmp2 = tmp2.next
            if tmp2 == None and tmp1 != None:
                while tmp1!= None:
                    if tmp1.val + carry >= 10:
                        carry = 1
                        tmp3.next = ListNode(tmp1.val + carry - 10)
                    else:
                        tmp3.next = ListNode(tmp1.val + carry)
                        carry = 0
                    tmp3 = tmp3.next
                    tmp1 = tmp1.next
            if carry == 1:
                tmp3.next = ListNode(1)
            return l3
    
    
    l1 = ListNode(2)
    l1.next = ListNode(4)
    l1.next.next = ListNode(3)
    l2 = ListNode(5)
    l2.next = ListNode(6)
    l2.next.next = ListNode(4)
    sol = Solution()
    l3 = sol.addTwoNumbers(l1, l2)
    print(l3.val)
    print(l3.next.val)
    print(l3.next.next.val)

**需要注意的是python对于链表的构造以及分析**

--------------------

## C++ ##

struct ListNode{
        int val;
        ListNode * next;
        ListNode(int x) : val(x), next(NULL);
    };

**ListNode(int x) is a constructor and is called when a ListNode is created. The : val(x), next(NULL) part of it initializes the struct’s members. This means set val = x and next = NULL. The \{\} is the code to be run for this method, in this case it is an empty code block.**

[70]: /images/20220515/200df4b8338844bf93dd578fb9594e5b.png