Merge Two Sorted Lists

来源：Leetcode

原帖：http://oj.leetcode.com/problems/merge-two-sorted-lists/

题目：
Merge two sorted linked lists and return it as a new list.
The new list should be made by splicing together the nodes of the first two lists.

代码：

 /**  
  * Definition for singly-linked list.  
  * struct ListNode {  
  *   int val;  
  *   ListNode *next;  
  *   ListNode(int x) : val(x), next(NULL) {}  
  * };  
  */  
   
 class Solution {  
 public:  
     ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {  
         ListNode dummy(0);  
         ListNode *cur = &dummy;  
         while (l1 && l2) {  
             if (l1->val <= l2->val) {  
                 cur->next = l1;  
                 l1 = l1->next;  
             } else {  
                 cur->next = l2;  
                 l2 = l2->next;  
             }  
             cur = cur->next;  
         }  
         cur->next = l1 != NULL ? l1 : l2;  
         return dummy.next;  
     }  
 };