链表_有序链表（插入删除遍历）

//链结点
public class Link {
    public long dData;
    public Link next;
    public Link(long dd) {
        dData=dd;    
    }
    public void displayLink() {
        System.out.print(dData+" ");
    }

}

public class SortedList {
    private Link first;
    public SortedList() {
        first=null;
    }
    //插入数据
    public void insert(long key) {
        Link newLink=new Link(key);
        //为找到插入点做准备
        Link previous=null;//记录插入点的左节点
        Link current=first;//记录插入点的右节点
        //寻找插入点
        while(current!=null&&key>current.dData) {//判断current！=null的原因是如果key是最大值，找不到比它大的，也需要退出循环
            //假设first端的数据是最小的
            previous=current;
            current=current.next;
        }
        //说明key是最小值
        if(previous==null)
            first=newLink;//改变first即可
        else
            previous.next=newLink;//不为空，与左侧需要连接
        
        newLink.next=current;//就算key是最大值，current会是null，这样也成立
        
    }
    //从first端删除
    public Link remove() {
        Link temp=first;
        first=first.next;
        return temp;
    }
    //遍历
    public void display() {
        System.out.println("List(Fist-->last):");
        Link current=first;
        while(current!=null) {
            current.displayLink();
            current=current.next;
        }
        System.out.println();
    }

}

public class Test {

    public static void main(String[] args) {
        SortedList theSortedList=new SortedList();
        theSortedList.insert(20);
        theSortedList.insert(40);
        theSortedList.display();
        theSortedList.insert(10);
        theSortedList.insert(30);
        theSortedList.insert(50);
        theSortedList.insert(55);
        theSortedList.display();
        theSortedList.remove();
        theSortedList.display();
    

    }

}