注意点：递归实现
public class ListNode {
int val;
ListNode next = null;
ListNode(int val) {
this.val = val;
}
}
public class Solution {
public ListNode Merge(ListNode list1,ListNode list2) {
if(list1 == null)
return list2;
if(list2 == null)
return list1;
ListNode head = null;
if(list1.val > list2.val)
{
head = list2;
head.next = Merge(list1,list2.next);
}else
{
head = list1;
head.next = Merge(list1.next,list2);
}
return head;
}
}
