Merge Two Sorted Lists

 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 mergeTwoLists(ListNode l1, ListNode l2) {
14         ListNode mergehead=new ListNode(0);
15         ListNode p=mergehead;
16         ListNode p1=l1;
17         ListNode p2=l2;
18         if(p1==null&&p2==null){
19             return null;
20         }
21         while(p1!=null||p2!=null){
22             int v1=0;
23             if(p1!=null&&p2!=null){
24                  ListNode newNode=new ListNode(p1.val>p2.val?p2.val:p1.val);
25                  p.next=newNode;
26                  p=newNode;
27                  if(p1.val>p2.val){
28                       p2=p2.next;
29                  }else{
30                       p1=p1.next;
31                  }
32             }else{
33                 if(p1==null){
34                     ListNode newNode=new ListNode(p2.val);
35                     p.next=newNode;
36                     p=newNode;
37                     p2=p2.next;
38                 }else{
39                     ListNode newNode=new ListNode(p1.val);
40                     p.next=newNode;
41                     p=newNode;
42                     p1=p1.next;
43                 }
44             }
45         }
46         return mergehead.next;
47     }
48 }