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无头单向不循环链表

main函数（测试）：

public class Demo11 {       public static void main(String[] args) {           MyList list = new MyList();        list.create();//穷举建4个节点，若链表为空直接添加，若不为空则尾插        list.show();        list.addHead(6);//头插6        list.show();        list.addLast(8);//尾插8        list.show();        list.create();        list.show();        list.addAny(999,9);//9位置插入999节点        list.show();        System.out.println(list.size);//输出长度        System.out.println("-------------1--------------");        System.out.println(list.Key(999));//查找是否有999        System.out.println(list.keyNum(999));//查找999的下标        System.out.println("--------------2-------------");        list.delKey(999);//删除数据为5的第一个节点        list.show();        System.out.println(list.size);        System.out.println("------------3--------------");        list.del(1);//删除所有为1的节点        list.show();        System.out.println(list.size);        System.out.println("------------4---------------");        System.out.println(list.midNode().val);//输出中间节点的值        list.inverse();//逆序        list.show();        System.out.println("-------------5--------------");        System.out.println(list.back(4).val);        System.out.println("----------6-----------------");        list.sort(4);        list.show();        System.out.println("------------7---------------");        list.addLast(1);        list.addLast(2);        list.addLast(1);        System.out.println(list.plalindrome());        System.out.println("-------------8--------------");        list = new MyList();        list.create();        list.ringC();        System.out.println(list.ring());        System.out.println(list.ringB());        System.out.println("-------------9--------------");        list = new MyList();        list.addLast(1);        list.addLast(1);        list.addLast(2);        list.addLast(2);        list.addLast(2);        list.addLast(4);        list.addLast(5);        list.clear();        list.show();    }}

链表及节点

public class MyList {       public Node head = null;    public int size = 0;//获取长度    public void create() {   //穷举        if (size==0){           Node node1 = new Node(1);        Node node2 = new Node(2);        Node node3 = new Node(3);        Node node4 = new Node(4);        node1.next = node2;        node2.next = node3;        node3.next = node4;        this.head = node1;        size = 4;        }else{               Node node1 = new Node(1);            Node node2 = new Node(2);            Node node3 = new Node(3);            Node node4 = new Node(4);            node1.next = node2;            node2.next = node3;            node3.next = node4;            Node cur = this.head;            for (;cur.next!=null;cur = cur.next);            cur.next=node1;            size = size+4;        }    }    public void addHead(int val){   //头插法        Node node = new Node(val);        node.next = this.head;        this.head = node;        size ++;    }    public void addLast(int val) {   //尾插法        Node cur = this.head;        if (cur == null){               Node node = new Node(val);            this.head = node;        }        for (;cur != null;){               if (cur.next == null) {                   Node node = new Node(val);                cur.next = node;                size ++;                return;            }            cur = cur.next;        }    }    public void addAny(int val,int pos){   //任意位置插入，头结点为0        Node cur = this.head;        int i;        if (pos<0||pos>size){               System.out.println("pos位置不合法");            return ;        }else if (pos == 0){               Node add = new Node(val);            add.next = cur;            this.head = add;            size++;            return;        }        for (i = 1; i 
   
    size){               return null;        }        for (;k>0;k--){               fast=fast.next;        }        for (;fast != null;){               fast=fast.next;            slow=slow.next;        }        return slow;    }    public void sort(int x){   //排序        if (head ==null){               return;        }        Node af = null;        Node ae = null;        Node bf = null;        Node be = null;        Node cur = this.head;        for (;cur !=null;cur=cur.next){               if (cur.val < x){                   if (af == null){                       af = cur ;                    ae = cur ;                }else {                       ae.next = cur;                    ae = cur;                }            }else {                   if (bf == null){                       bf = cur ;                    be = cur ;                }else {                       be.next = cur;                    be = cur;                }            }        }        be.next=null;        if (af == null){               this.head = bf;            return;        }else            this.head = af;        if (bf == null){               ae.next = null;            this.head = af;            return;        }        ae.next=bf;        return;    }    public boolean plalindrome(){   //判断回文        Node prev =midNode();        Node cur = prev.next;        Node curNext = cur.next;        for (;curNext!=null;){               cur.next = prev;            prev = cur;            cur = curNext;            curNext = curNext.next;        }        cur.next = prev;        prev = this.head;        for (;prev != cur && prev.next != cur ;){               if (cur.val != prev.val){                   return false;            }            prev=prev.next;            cur = cur.next;        }        if (cur.val != prev.val){               return false;        }        return true;    }    //清除重复    public void clear() {           Node cur = this.head;        for (;cur.next!=null;){               if (cur.val == cur.next.val){                   del(cur.val);            }            cur=cur.next;        }    }    //创建环    public void ringC(){           Node cur = this.head.next;        Node prev = cur;        for (;cur.next!=null;){               cur = cur.next;        }        cur.next = prev;    }    //判断环    public boolean ring(){           Node fast = this.head;        Node slow = this.head;        for (;fast!=null && fast.next!=null;){               fast=fast.next.next;            slow=slow.next;            if (slow == fast){                   break;            }        }        if (fast == null || fast.next==null){               return false;        }        return true;    }    //判断环，并输出环的起点    public int ringB(){           Node fast = this.head;        Node slow = this.head;        for (;fast!=null && fast.next!=null;){               fast=fast.next.next;            slow=slow.next;            if (slow == fast){                   break;            }        }        if (fast == null || fast.next==null){               return -1;        }        fast = this.head;        for (;fast != slow;){               fast = fast.next;            slow = slow.next;        }        return slow.val;    }}class Node {       public int val;    public Node next;    public Node(int val) {   //构造函数        this.val = val;    }}