add-two-numbers(单链表相加)

题目描述

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 newNode = new ListNode(0);
        ListNode node = newNode;
        int cap = 0;
        while(l1 != null || l2 != null) {
            if(l1 != null) {
                cap += l1.val;
                l1 = l1.next;
            }
            if(l2 != null) {
                cap += l2.val;
                l2 = l2.next;
            }
            node.next = new ListNode(cap % 10);
            cap = cap / 10;
            node = node.next;

        }

        if(cap != 0) {
            node.next = new ListNode(cap);
        }
        return newNode.next;
    }
}