Leetcode之add Two Numbers

09 June 2014

这题比较水。

Add Two Numbers

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

解法：先遍历相加，再处理进位，注意{5}{5}的这种情况，需要增加一个节点。

这题数字是逆序存储，如果数字是顺序存储呢？方法也很多，容易想到的是每次乘以10将链表转为整数然后相加，结果再转成链表。或者将两个链表重新头插一边转换成这个问题。

代码如下：

//{java}
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode p=l1,q=l2,t=l1;
        while(p!=null && q!=null)
        {
            p.val+=q.val;
            t=p;
            p=p.next;
            q=q.next;
        }
        while(q!=null)
        {
            t.next=q;
             t=t.next;
            q=q.next;
        }
        p=l1;
        int jinwei=0;
        while(p!=null)
        {
            p.val+=jinwei;
            jinwei=p.val/10;
            p.val%=10;
            t=p;
            p=p.next;
        }
        if(jinwei==1)
            t.next=new ListNode(1);
        return l1;
    }
}

LeetCode 47

LeetCode，面试，链表，遍历 1

Leetcode之add Two Numbers 链表存数运算

Add Two Numbers