标签：
问题描述：
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
解题思路：
设立一个头ListNode和尾ListNode，两个List分别从头开始，两两相加并且设立进位carry，如果相加超过10则carry为1,否则为零。同时需要考虑一个List还有长度，另一个已经结束的情况。
代码如下：
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * int val; 5 * ListNode next; 6 * ListNode(int x) { 7 * val = x; 8 * next = null; 9 * } 10 * } 11 */ 12 public class Solution { 13 public ListNode addTwoNumbers(ListNode l1, ListNode l2) { 14 15 ListNode head = new ListNode(0); 16 ListNode tail = head; 17 int sum = 0; 18 int carry = 0; 19 20 while(l1 != null || l2 != null){ 21 if(l1 == null){ 22 sum = l2.val + carry; 23 l2 = l2.next; 24 } 25 else if (l2 == null){ 26 sum = l1.val + carry; 27 l1 = l1.next; 28 } 29 else{ 30 sum = l1.val + l2.val + carry; 31 l1 = l1.next; 32 l2 = l2.next; 33 } 34 35 if(sum >= 10){ 36 carry = sum / 10; 37 sum = sum % 10; 38 } 39 else{ 40 carry = 0; 41 } 42 43 tail.next = new ListNode(sum); 44 tail = tail.next; 45 } 46 47 if(carry != 0){ 48 tail.next = new ListNode(carry); 49 tail = tail.next; 50 } 51 52 return head.next; 53 } 54 }
Java [leetcode 2] Add Two Numbers
标签：
原文地址：http://www.cnblogs.com/zihaowang/p/4455777.html
