leetcode_2_Add Two Numbers

标签：leetcode   链表   

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

思路：

两个链表分别从第一个结点开始分别相加，大于10的进位和下两个结点的值一起相加直至两个结点都到链表的结尾，如果到链表结尾仍然有进位，创建一个新的节点放在较长的那个链表的后面。

代码：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public  ListNode addTwoNumbers(ListNode l1, ListNode l2) {
	        int len1=0,len2=0;
	        int sum=0,flag=0;
	        ListNode pListNode=null;
	        for(pListNode=l1;pListNode!=null;pListNode=pListNode.next)
	        {
	        	if(pListNode!=null)
	        		len1++;
	        }
	        for(pListNode=l2;pListNode!=null;pListNode=pListNode.next)
	        {
	        	if(pListNode!=null)
	        		len2++;
	        }
	        if(len1>len2)
	        	pListNode=l1;
	        else
	        	pListNode=l2;
	        ListNode listNode=pListNode;
	        while(l1!=null&&l2!=null)
	        {
	        	sum=l1.val+l2.val+flag;
	        	pListNode.val=sum%10;
	        	pListNode=pListNode.next;
	        	flag=sum/10;
	        	l1=l1.next;
	        	l2=l2.next;
	        }
	        while(pListNode!=null)
	        {
	        	sum=pListNode.val+flag;
	        	pListNode.val=sum%10;
	        	flag=sum/10;
	        	if(flag==0)
	        		break;
	        	pListNode=pListNode.next;
	        }
	        if(flag!=0)
	        {
	        	ListNode li =listNode;
	        	while(li.next!=null)
	        		li=li.next;
	        	ListNode temp=new ListNode(flag);
	        	li.next=temp;
	        }
	    	return listNode;
	    }

结果：

leetcode_2_Add Two Numbers

标签：leetcode   链表   

原文地址：http://blog.csdn.net/mnmlist/article/details/43198615