首先想到的是走到其中一个链表的尽头，然后把剩余的链表中的值放入写的链表，返回，但是自己写的代码好长。
1 struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) { 2 int g,s=0,stmp; 3 struct ListNode *pl,*ptmp,*pi; 4 pl=NULL; 5 while(l1&&l2) 6 { 7 g=l1->val+l2->val; 8 g+=s; 9 stmp=g/10; 10 g%=10; 11 struct ListNode* ptmp=(struct ListNode *)malloc(sizeof(struct ListNode)); 12 ptmp->next=NULL; 13 ptmp->val=g; 14 if(pl==NULL) 15 { 16 pl=ptmp; 17 pi=pl; 18 } 19 else 20 { 21 pi->next=ptmp; 22 pi=pi->next; 23 } 24 s=stmp; 25 l1=l1->next; 26 l2=l2->next; 27 } 28 if(l1==NULL) 29 l1=l2; 30 while(l1) 31 { 32 g=l1->val; 33 g+=s; 34 stmp=g/10; 35 g%=10; 36 struct ListNode *ptmp=malloc(sizeof(struct ListNode)); 37 ptmp->next=NULL; 38 ptmp->val=g; 39 pi->next=ptmp; 40 pi=pi->next; 41 s=stmp; 42 l1=l1->next; 43 } 44 if(s) 45 { 46 struct ListNode *ptmp=malloc(sizeof(struct ListNode)); 47 ptmp->next=NULL; 48 ptmp->val=s; 49 pi->next=ptmp; 50 } 51 return pl; 52 }
Python:
1 # Definition for singly-linked list. 2 # class ListNode(object): 3 # def __init__(self, x): 4 # self.val = x 5 # self.next = None 6 7 class Solution(object): 8 def addTwoNumbers(self, l1, l2): 9 """ 10 :type l1: ListNode 11 :type l2: ListNode 12 :rtype: ListNode 13 """ 14 tmp = l1 15 up = 0 16 while l1 and l2: 17 l1.val += (l2.val+up) 18 if l1.val > 9: 19 up = 1 20 l1.val %= 10 21 else: 22 up = 0 23 p1,p2 = l1,l2 24 l1,l2 = l1.next,l2.next 25 if not l1 and not l2: 26 if up: 27 p1.next = ListNode(up) 28 return tmp 29 if l2: 30 p1.next = l2 31 l1 = p1.next 32 while l1 and up: 33 l1.val += up 34 if l1.val >9: 35 up=1 36 l1.val %= 10 37 else: 38 up = 0 39 p1 = l1 40 l1 = l1.next 41 if up: 42 p1.next = ListNode(up) 43 return tmp 44