leetcode[2]Add Two Numbers
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
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) { if(l1==NULL)return l2; if(l2==NULL)return l1; ListNode *l3=NULL; ListNode *p=l3; int flag=0; int res=0; while(l1!=NULL||l2!=NULL) { res=flag; if(l1!=NULL) { res+=l1->val; l1=l1->next; } if(l2!=NULL) { res+=l2->val; l2=l2->next; } if(l3==NULL) { l3=new ListNode(res%10); p=l3; } else { p->next=new ListNode(res%10); p=p->next; } flag=res/10; } if(flag) { p->next=new ListNode(flag); p=p->next; } return l3; } };