/*
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;
        //设置临时链表head
        ListNode head = new ListNode(0);
        ListNode p =head;
        //开始拼接新链表
        while(list1 !=null && list2 !=null){
            if(list1.val >= list2.val){
                p.next = list2;
                list2 = list2.next;
            }else{
                p.next = list1;
                list1 = list1.next;
            }
            p = p.next; 
        }
        if(list1 == null) p.next = list2;
        if(list2 == null) p.next = list1;
        return head.next;
    }
}