Java中单链表的部分操作总结

1.定义数据类Node 来存储结点信息

public class Node {    Node next = null;    int data;    public Node(int data) {        this.data = data;    }    public String toString() {        return this.data + "";    }}

2.单链表操作代码如下：

import java.util.Hashtable;public class MyLinkedList {    static Node head = null;    public static void main(String[] args) {        MyLinkedList list = new MyLinkedList();        list.add(5);        list.add(3);        list.add(2);        list.add(3);        System.out.print("length:" + list.length() + "\n");        list.print();        /*         * 删除指定点         */        list.deleteNode(4);        System.out.print("删除指定点后  length:" + list.length() + "\n");        list.print();        /*         * 指定点处插入数据         */        list.addNode(7, 8);        System.out.print("指定点处插入数据后 length:" + list.length() + "\n");        list.print();        /*         * 排序         */        list.orderList();        list.print();        /*         * 刪除重复数据         */        list.deleteDuplecate2(head);        list.print();        /*         * 找出单链表中倒数第K个元素         */        System.out.print(list.findElemFromEnd(head, 3));        /*         * 单链表的反转         */        list.ReverseIteratively(head);        list.print();        /*         * 从尾到头输出单链表         */        list.printListRevaesely(head);        list.print();        /*         * 寻找单链表的中间结点         */         System.out.println(list.searchNode(head));    }    /*     * 刪除链表中重复数据：方法一 时间复杂度低，但是需要额外的空间     */    public void deleteDuplecate1(Node head) {        Hashtable<Integer, Integer> table = new Hashtable<Integer, Integer>();        Node tmp = head;        Node pre = null;        while (tmp != null) {            if (table.containsKey(tmp.data)) {                pre.next = tmp.next;            } else {                table.put(tmp.data, 1);                pre = tmp;            }            tmp = tmp.next;        }    }    /*     * 刪除链表中重复数据：方法二 不需要额外的空间， 时间复杂度高     */    public void deleteDuplecate2(Node head) {        Node p = head;        while (p != null) {            Node q = p;            while (q.next != null) {                if (q.next.data == p.data) {                    q.next = q.next.next;                } else {                    q = q.next;                }            }            p = p.next;        }    }    /*     * 找出单链表中的倒数第K个元素     */    public Node findElemFromEnd(Node head, int k) {        if (k < 1 || k > length()) {            return null;        }        Node p1 = head;        Node p2 = head;        for (int i = 0; i < k - 1; i++) {            p1 = p1.next;        }        while (p1 != null) {            p1 = p1.next;            p2 = p2.next;        }        return p2;    }    /*     * 找出单链表的中间结点     */    public Node searchNode(Node head) {        Node p = this.head;        Node q = this.head;        while (p != null && p.next != null && p.next.next != null) {            p = p.next.next;            q = q.next;        }        return q;    }    /*     * 向链表尾部添加数据     */    public void add(int data) {        Node newNode = new Node(data);        if (head == null) {            head = newNode;            return;        }        Node tmp = head;        while (tmp.next != null) {            tmp = tmp.next;        }        tmp.next = newNode;    }    /*     * 在第index个结点插入数据     */    public Boolean addNode(int index, int data) {        Node newNode = new Node(data);        if (index < 1) {            return false;        }        if (index == 1) {            newNode.next = head;            head = newNode;            return true;        }        if (index > length()) {            add(data);            return true;        }        int i = 2;        Node preNode = head;        Node curNode = preNode.next;        while (curNode != null) {            if (i == index) {                preNode.next = newNode;                newNode.next = curNode;                return true;            }            preNode = curNode;            curNode = curNode.next;            i++;        }        return true;    }    /*     * 单链表的反转     */    public void ReverseIteratively(Node head) {        Node pReversedHead = head;        Node pNode = head;        Node pPrev = null;        while (pNode != null) {            Node pNext = pNode.next;            if (pNext == null) {                pReversedHead = pNode;            }            pNode.next = pPrev;            pPrev = pNode;            pNode = pNext;        }        this.head = pReversedHead;    }    /*     * 从尾到头输出单链表：采用递归实现，单链表实际上并没有反转     */    public void printListRevaesely(Node pListHead) {        if (pListHead != null) {            printListRevaesely(pListHead.next);            System.out.println(pListHead.data);        }    }    /*     * 链表中的排序     */    public void orderList() {        Node nextNode = null;        Node curNode = head;        int tmp = 0;        while (curNode.next != null) {            nextNode = curNode.next;            while (nextNode != null) {                if (curNode.data > nextNode.data) {                    tmp = curNode.data;                    curNode.data = nextNode.data;                    nextNode.data = tmp;                }                nextNode = nextNode.next;            }            curNode = curNode.next;        }    }    /*     * 删除第index个结点     */    public Boolean deleteNode(int index) {        if (index < 1 || index > length()) {            return false;        }        if (index == 1) {            head = head.next;            return true;        }        int i = 2;        Node preNode = head;        Node curNode = preNode.next;        while (curNode != null) {            if (i == index) {                preNode.next = curNode.next;                return true;            }            preNode = curNode;            curNode = curNode.next;            i++;        }        return true;    }    /*     * 返回结点的长度     */    public int length() {        int length = 0;        Node tmp = head;        while (tmp != null) {            length++;            tmp = tmp.next;        }        return length;    }    /*     * 打印链表的所有节点     */    public void print() {        Node tmp = head;        while (tmp != null) {            System.out.print(tmp.data + "——>");            tmp = tmp.next;        }        System.out.print("尾部" + "\n");    }}