java双向链表

package datastruct;

/* *双向链表的的结点 */ public class DoubleNode { private DoubleNode previous;// 指向前一个接点的指针 private int value;// 接点保存的值 private DoubleNode next;// 指向下一个接点的指针

public DoubleNode(int value) {   super();   this.value = value;   this.previous = this;//初始时指向自身 this.next = this;//初始时指向自身 }

public DoubleNode() {   // TODO Auto-generated constructor stub }

public DoubleNode getPrevious() {   return previous; }

public void setPrevious(DoubleNode previous) {   this.previous = previous; }

public int getValue() {   return value; }

public void setValue(int value) {   this.value = value; }

public DoubleNode getNext() {   return next; }

public void setNext(DoubleNode next) {   this.next = next; }

}

package datastruct; /** * 双向链表 * @author dell * */ public class MyDoubleList {

private DoubleNode head;// 头结点，初始值为null private int length = 0;// 链表的长度

public int getLength() {   return length; }

public void setLength(int length) {   this.length = length; }

public MyDoubleList() {   head = new DoubleNode(); }

public DoubleNode getHead() {   return head; }

public void setHead(DoubleNode head) {   this.head = head; }

/**   * @param args   */ public static void main(String[] args) {   MyDoubleList ml = new MyDoubleList();   ml.add(new DoubleNode(1));   ml.add(new DoubleNode(2));   ml.add(new DoubleNode(3));   ml.add(new DoubleNode(4));   ml.add(new DoubleNode(5));   ml.add(new DoubleNode(6));   ml.add(new DoubleNode(7));   ml.remove(new DoubleNode(3));    ml.insert(new DoubleNode(11), 3);

  while (ml.head != null) {    System.out.println(ml.head.getValue());    ml.head = ml.head.getPrevious();   } }

/**   * 添加新节点 *   * @param n要加入的节点 */ public void add(DoubleNode n) {   head.setNext(n);//头结点的next指针指向n   //n的前驱指针指向head   n.setPrevious(head);   head = n;// 指针移动 this.length++; }

/**   * 删除某个节点 *   * @param n要删除的节点 */ public void remove(DoubleNode n) {   if (head == null)    return;   if (n.getValue() == this.head.getValue()) {    head = head.getPrevious();    head.setNext(null);    // head.setp    return;   }

  DoubleNode pre = head;// 当前节点，初始值为头结点 DoubleNode cur = head.getPrevious();// 当前节点的前驱节点 while (cur != null) {    if (cur.getValue() == n.getValue()) {     pre.setPrevious(cur.getPrevious());     cur.getPrevious().setNext(pre);     // pre.getNext().setNext(cur.getNext());     return;//    }

   pre = pre.getPrevious();// 移动指针 cur = cur.getPrevious();// 移动指针 }

}

/**   *插入节点 */ public void insert(DoubleNode n, int i) {   if (head == null) {    add(n);    return;   }

  DoubleNode pre = head;   DoubleNode cur = head.getPrevious();   int j = 1;   while (cur != null) {    if (j == i-1) {     cur.setNext(n);     n.setPrevious(cur);     n.setNext(pre);     pre.setPrevious(n);     return;    }

   pre = pre.getPrevious();// 移动指针 cur = cur.getPrevious();// 移动指针 j++;   }

} }