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. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { * val = x; * next = null; * } * } */ public class Solution { public ListNode addTwoNumbers(ListNode l1, ListNode l2) { int carry = 0; ListNode res = new ListNode(0); ListNode head = res;//m1 here, make running pointer start from null while(l1 != null||l2 != null){ if(l1!=null){ // l1 l2 check separately carry += l1.val; l1 = l1.next; } if(l2 != null){ carry += l2.val; l2 = l2.next; } head.next = new ListNode(carry%10); head = head.next; carry = carry/10; } if(carry==1) head.next=new ListNode(1); return res.next; } }
mistake: 1)when create new listnode, make it new ListNode() 2)l1 l2 do calculation separately