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) {
// Note: The Solution object is instantiated only once and is reused by each test case.
if (l1 == null || l2 == null) return null;
ListNode head = new ListNode(-1);
ListNode cur = head;
boolean carry = false;
while (true) {
int curval = l1.val + l2.val;
if (carry == true)
curval += 1;
if (curval >= 10) {
curval = curval % 10;
carry = true;
} else
carry = false;
cur.next = new ListNode(curval);
cur = cur.next;
if (l1.next == null && l2.next == null) break;
// 保证两个链表的长度一样,若不一样,在短的那个前面补0
l1 = (l1.next == null) ? new ListNode(0) : l1.next;
l2 = (l2.next == null) ? new ListNode(0) : l2.next;
}
if (carry == true) {
cur.next = new ListNode(1);
}
return head.next;
}
}