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) {        ListNode p1 = l1;        ListNode p2 = l2;        ListNode h = new ListNode(0);//创建一个头结点        ListNode r = h;//设立一个尾指针        int carry = 0;//进位        int sum = 0;//对应位及进位相加之和        while(p1!=null||p2!=null) {                        if(p1!=null&&p2!=null){                sum = p1.val+p2.val+carry;                p1 = p1.next;                p2 = p2.next;            }                        else {                if(p1==null) {                    sum = p2.val+carry;                    p2 = p2.next;                }                else {                    sum = p1.val+carry;                    p1 = p1.next;                }            }                        if(sum>=10) {                sum = sum-10;                carry = 1;            }            else {                carry = 0;            }            ListNode p = new ListNode(sum);            r.next = p;            r = p;        }        if(carry==1) {            ListNode p = new ListNode(1);            r.next = p;            r = p;        }        return h.next;    }}