链表的java实现与时间和空间复杂度分析

来源：互联网发布：linux top 编辑：程序博客网时间：2024/05/22 05:02

今天主要编写了链表，其具体代码如下：

import edu.princeton.cs.algs4.StdIn;import edu.princeton.cs.algs4.StdOut;public class LinkList {    private Node head;    public LinkList() {        // TODO Auto-generated constructor stub        head = new Node("");    }    public void Insert() {        String string;        Node node = head;        while (!(string = StdIn.readString()).equals("#")) {            Insert(node, new Node(string));            node = node.next;        }    }    /**     * insert node n2 after node n1     * @param n1     * @param n2     */    public void Insert(Node n1, Node n2) {        if (n1 == null || n2 == null);        else {            Node n3 = n1.next;            n1.next = n2;            n2.next = n3;        }    }    /**     * delete the k-th node     * @author Bjy_PC     *     */    public String delete(int k) {        if (head.next == null) return null;        Node node = head;        int count = 0;        String string = new String();        while (node.next != null) {            if (k - 1 == count) {                string = node.next.value;                node.next = node.next.next;                break;            }            node = node.next;            count++;        }        return string;    }    /**     * find the max element using recursion     * @author Bjy_PC     *     */    public Node max() {        return max(head.next, head.next.next);          }    public Node max(Node n1, Node n2) {        if (n2.next == null)  return n1;        else                  return max(n1.value.compareTo(n2.value) >= 0? n1:n2, n2.next);         }    /**     * show the list     * @author Bjy_PC     *     */    @Override    public String toString() {        // TODO Auto-generated method stub        Node node = head;        String string = new String("");        while (node.next != null) {            node = node.next;            string += node.value + "--->";        }        return string;    }    /**     * reverse the linklist     * @author Bjy_PC     *     */    public Node reverse() {        Node first = head.next;        Node second = first.next;        Node reverse = null;        if (first == null || second == null) return this.head.next;        else {            while (first != null) {                first.next = reverse;                reverse = first;                first = second;                if (second != null)                     second = second.next;            }        }        head.next = reverse;        return reverse;         }     class Node {        Node next;        String value;        public Node(String item) {            // TODO Auto-generated constructor stub            this.value = item;            this.next = null;        }    }    public static void main(String[] args) {        // TODO Auto-generated method stub        LinkList list = new LinkList();        list.Insert();        StdOut.println(list);        list.delete(1);        list.Insert(list.head.next.next, list.new Node("perfect"));        StdOut.println(list);        StdOut.println("max value :" + list.max().value);        list.reverse();        StdOut.println(list);    }}

其中每个操作的时间复杂度最多为线性的，对空间复杂度来说，Node节点占用72字节，其中Node对象开销16个字节，内部类占用8字节的额外开销，指向Node的引用占用8个字节，String对象占用40个字节。则长度为N的链表至少需要24 + 72*N个字节(不包括字符串数组的字节数），其中LinkList对象有16个字节的对象开销，head节点的引用占用8个字节。

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