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

 

Code:

 

class Solution {public:    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {        ListNode *start= new ListNode(0);        start->next=l1;         while(l1||l2){            if(l1&&l2){                l1->val=l1->val+l2->val;                if(l1->val>9){                    l1->val=l1->val%10;                    if(l1->next)                        l1->next->val=l1->next->val+1;                    else if(l2->next){                        l1->next=l2->next;                        l2->next->val=l2->next->val+1;                        l2=NULL;                    }else{                        ListNode *carry= new ListNode(1);                        l1->next=carry;                    }                   }                if(!l1->next&&l2->next){                    l1->next=l2->next;                    l2=NULL;                }                l1=l1->next;                if(l2)                    l2=l2->next;            }else if(l1){                if(l1->val>9){                    l1->val=l1->val%10;                    if(l1->next)                        l1->next->val=l1->next->val+1;                    else{                        ListNode *carry= new ListNode(1);                        l1->next=carry;                    }                }                l1=l1->next;            }        }        l1=start->next;        delete start;        return l1;    }};