题解 | #合并两个排序的链表#

/*
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 && list2 == null){
            return null;
        }
        if(list1 == null){
            return list2;
        }
        if(list2 == null){
            return list1;
        }
        ListNode result = new ListNode(0);
        ListNode p1=list1,p2=list2,p3=result;
        while(p1!=null||p2!=null){
            p3.next=new ListNode(0);
            p3=p3.next;
            if(p1==null&&p2!=null){
                p3.val=p2.val;
                p2 = p2.next;
            }
            if(p2==null&&p1!=null){
                p3.val=p1.val;
                p1=p1.next;
            }
            if(p1!=null&&p2!=null){
                if(p1.val>p2.val){
                    p3.val=p2.val;
                    p2=p2.next;
                }else{
                    p3.val=p1.val;
                    p1=p1.next;
                }
            }
            p3.next=null;
        }
        return result.next;
    }
}