如何创建自己的单个链表

时间:2012-12-02 22:58:30

标签: java linked-list

我正在尝试将使用ArrayLists的代码转换为适用于单链接列表的代码。数组列表由先前创建的Shape对象组成,我知道工作。然后,可以将新形状添加到数组列表的末尾。此外,可以使用索引引用从此列表中删除特定形状。但是,当我将其切换到链接列表时,我得不到我需要的东西。这是数组列表的代码:

import java.util.ArrayList;

public class ShapeLinkedList {
    ArrayList<Shape> list = new ArrayList<Shape>();

    public ShapeLinkedList() {
    }

    public void addToRear(Shape shape) {
        list.add(shape);
        System.out.println("Added "+shape);
    }

    public Shape get(int index) {
        return list.get(index);
    }

    public int size() {
        return list.size();
    }

    public Shape remove(int index) {
        Shape temp = list.remove(index);
        System.out.println("Removed "+temp);
        return temp;
    }
}

我无法改变方法的名称,我必须使用所有相同的方法。所以这就是我到目前为止的链表:

public class ShapeLinkedList {
    ShapeNode head;
    int count = 0;

    public ShapeLinkedList() {}

    public void addToRear(Shape shape) {
        ShapeNode end = new ShapeNode(shape);
        if (head == null) {
            head = end;
        }
        //loop through Linked List until we find the end of the list
        while (head.next != null) {
            head = head.next;
            count++;
        }
        //set the new node to the Shape shape and the next one will be null
        head.next = end;
        count++;
        //System.out.println("Added " + shape);
    }

    public Shape get(int index) {
        for (int i = 0; i <= index; i++) {

        }
        Shape rem = ;
        return rem
    }

    public int size() {
        return count;
    }

    public Shape remove(int index) {
        if (index == 0) {
            Shape temp = head;
            head = head.next;
        } else if () {
            Shape temp = ;
        }
        //System.out.println("Removed " + temp);
        return temp;
    }

    private class ShapeNode {
        Shape shp;
        ShapeNode next;

        public ShapeNode(Shape shp) {
            this.shp = shp;
            next = null;
        }
    }
}

我需要帮助构造Shape的getter,因为我不知道如何找到LinkedList的索引,我不知道如何在该索引处引用特定的shape类型。另外,我需要有关remove方法的帮助。我觉得一旦我得到了第一个吸气剂的必要信息,我遇到了麻烦,我应该能够解决我的第二个问题。有没有人有有用的建议?

1 个答案:

答案 0 :(得分:0)

 public Shape get(int index) {
        ShapeNode temp = head;
        while(index-- > 0) {
            temp = temp.next;
        }
        if(temp == null)
            throw new IndexOutOfBoundsException("Invalid index : " + index);
        Shape rem = temp.shp;
        return rem;
    }

但这是O(n)是LinkedList。