LeetCode 合并两个有序链表

题目

代码

迭代法：

/** 
  * Definition for singly-linked list. 
  * public class ListNode { 
  *     public int val;
  *     public ListNode next; 
  *     public ListNode(int x) { val = x; } 
  * } 
  */
public class Solution 
{    
    public ListNode MergeTwoLists(ListNode l1, ListNode l2) 
    {        
        if (l1 == null)            
           return l2;        
        if (l2 == null)            
           return l1;        
        if (l1.val < l2.val)        
        {            
           l1.next = MergeTwoLists(l1.next, l2);            
           return l1;        
        }        
        else        
        {            
           l2.next = MergeTwoLists(l1, l2.next);            
           return l2;        
        }    
    }
}