leetcode 21--Merge Two Sorted Lists 链表 合并

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.

有序链表合并，参考单链表的归并排序。其实这个是是链表归并排序的一部分。

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