java版本链表MyLinkedList程序及测试用例demo

１.单链表MyLinkedList实例

package com.hooware.mylinked;

/**
 * @author hooware
 * @param 
 */
public class MyLinkedList<E> {

    /**
     * size : 链表长度
     * head : 链表虚拟头结点
     */
    private int size;
    private Node head;

    public MyLinkedList() {
        this.head = new Node();
    }

    class Node {
        Node next;
        E val;

        public Node() {
        }

        public Node(E val) {
            this.val = val;
        }
    }

    public int getSize() {
        return size;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public void addFirst(E value) {
        Node node = new Node(value);
        Node temp = head.next;
        head.next = node;
        node.next = temp;
        size++;
    }

    public void addLast(E value) {
        Node node = new Node(value);
        Node cur = head;
        while (cur.next != null) {
            cur = cur.next;
        }
        cur.next = node;
        size++;
    }

    public void add(E value, int index) {
        if (index < 0)
            throw new IllegalArgumentException("索引不合法");
        if (index > size) {
            addLast(value);
        } else {
            Node node = new Node(value);
            Node cur = head;
            for (int i = 0; i < index; i++) {
                cur = cur.next;
            }
            Node temp = cur.next;
            cur.next = node;
            node.next = temp;
            size++;
        }
    }

    public E peek() {
        Node cur = head.next;
        if (cur == null) {
            return null;
        }
        return cur.val;
    }

    public E getFirst() {
        return peek();
    }

    public E getLast() {
        Node cur = head;
        if (cur.next == null) {
            return null;
        }
        while (cur.next != null) {
            cur = cur.next;
        }
        return cur.val;
    }

    public E removeFirst() {
        Node cur = head;
        if (cur.next == null) {
            return null;
        } else {
            E value = cur.next.val;
            cur.next = cur.next.next;
            size--;
            return value;
        }
    }

    public E removeLast() {
        Node cur = head;
        if (cur.next == null) {
            return null;
        } else {
            while (cur.next.next != null) {
                cur = cur.next;
            }
            E value = cur.next.val;
            cur.next = cur.next.next;
            size--;
            return value;
        }
    }

    public E remove(int index) {
        if (index < 0)
            throw new IllegalArgumentException("索引不合法");
        if (index >= size)
            return removeLast();
        Node cur = head;
        if (cur.next == null) {
            return null;
        }

        for (int i = 0; i < index; i++) {
            cur = cur.next;
        }
        E value = cur.next.val;
        cur.next = cur.next.next;
        size--;
        return value;
    }

    public E updateFirst(E val) {
        Node cur = head.next;
        if (cur == null) {
            return null;
        }
        E value = cur.val;
        cur.val = val;
        return value;
    }

    public E updateLast(E val) {
        Node cur = head.next;
        if (cur == null) {
            return null;
        }
        while (cur.next != null) {
            cur = cur.next;
        }
        E value = cur.val;
        cur.val = val;
        return value;
    }

    public E update(E val, int index) {
        if (index < 0)
            throw new IllegalArgumentException("索引不合法");
        if (index >= size)
            return updateLast(val);

        Node cur = head.next;
        if (cur == null) {
            return null;
        }
        for (int i = 0; i < index; i++) {
            cur = cur.next;
        }
        E value = cur.val;
        cur.val = val;
        return value;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder("MyLinkedList size is " + size + " !");
        if (size > 0) {
            sb.append(" head : ");
        }
        Node cur = head.next;
        while (cur != null) {
            if (cur.next == null) {
                sb.append(cur.val + " tail");
                cur = cur.next;
                continue;
            }
            sb.append(cur.val + "-->");
            cur = cur.next;
        }
        return sb.toString();
    }
}

1.测试单链表实例demo

package com.hooware.mylinked;

public class MyLinkDemo {
    public static void main(String[] args) {
//        test02();
//        test03();
//        test04();
//        test05();
//        test06();
//        test07();
//        test08();
        test09();
    }


    public static void test01() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println(list.getSize());
        System.out.println(list.isEmpty());
        list.addFirst(1);
        list.addFirst(2);
        list.addFirst(3);
        list.addFirst(4);
        list.addFirst(5);
        System.out.println(list.getSize());
        System.out.println(list.isEmpty());
        System.out.println(list);
    }

    public static void test02() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        list.addLast(1);
        list.addLast(2);
        list.addFirst(222);
        list.addLast(3);
        list.addLast(4);
        list.addFirst(5);
        System.out.println(list.getSize());
        System.out.println(list);
    }

    public static void test03() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println("peek : " + list.peek());
        System.out.println("getLast : " + list.getLast());
        list.add(10,0);
        list.add(11,0);
        list.add(12,0);
        //System.out.println("getLast : " + list.getLast());
        list.add(13,6);
        list.add(14,2);
        list.add(100,123);
        System.out.println(list.getSize());
        System.out.println(list);
        System.out.println("peek : " + list.peek());
        System.out.println("getLast : " + list.getLast());
    }

    public static void test04() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println("peek : " + list.peek());
        System.out.println("getLast : " + list.getLast());
        list.add(10,0);
        list.add(11,0);
        list.add(12,0);
        //System.out.println("getLast : " + list.getLast());
        list.add(13,6);
        list.add(14,2);
        System.out.println(list.getSize());
        System.out.println(list);
        System.out.println("peek : " + list.peek());
        System.out.println("getLast : " + list.getLast());

        Integer value1 = list.removeFirst();
        System.out.println("removeFirst 1 : " + value1);
        Integer value2 = list.removeFirst();
//        list.removeFirst();
//        list.removeFirst();
//        list.removeFirst();
        System.out.println("removeFirst 2 : " + value2);
        System.out.println(list);
    }

    public static void test05() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println("peek : " + list.peek());
        System.out.println("getLast : " + list.getLast());
        list.add(10,0);
        list.add(11,0);
        list.add(12,0);
        //System.out.println("getLast : " + list.getLast());
        list.add(13,6);
        list.add(14,2);
        System.out.println(list);
        Integer value1 = list.removeLast();
        System.out.println("removeLast 1 : " + value1);
        Integer value2 = list.removeFirst();
        System.out.println("removeFirst 2 : " + value2);
        System.out.println(list);
        System.out.println(list.removeLast());
        System.out.println(list.removeLast());
        System.out.println(list.removeLast());
        System.out.println(list.removeLast());
        System.out.println(list);
    }

    public static void test06() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        list.addFirst(1);
        list.addFirst(2);
        list.addFirst(3);
        list.addFirst(4);
        list.addFirst(5);
        list.addFirst(6);
        System.out.println(list);
        Integer val01 = list.remove(0);
        System.out.println(val01);
        System.out.println(list);

        Integer val02 = list.remove(8);
        System.out.println("val02 " + val02);
        System.out.println(list);

        Integer val03 = list.remove(2);
        System.out.println("val03 " + val03);
        System.out.println(list);
        System.out.println(list.remove(1));
        System.out.println(list.remove(1));
        System.out.println(list.remove(1));
        System.out.println(list.remove(1));
        System.out.println(list);

    }


    public static void test07() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println(list.updateFirst(100));
        list.addFirst(1);
        list.addFirst(6);
        System.out.println(list);
        Integer value = list.updateFirst(10);
        System.out.println(list);
        System.out.println(value);
    }

    public static void test08() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println(list.updateLast(100));
        list.addFirst(1);
        list.addFirst(6);
        System.out.println(list);
        Integer value = list.updateLast(10);
        System.out.println(list);
        System.out.println(value);
    }

    public static void test09() {
        MyLinkedList<Integer> list = new MyLinkedList<>();
        System.out.println(list.update(100,10));
        list.addFirst(1);
        list.addFirst(2);
        list.addFirst(3);
        list.addFirst(4);
        System.out.println(list);
        Integer value = list.update(10,2);
        System.out.println(list);
        System.out.println(value);
        System.out.println(list);
        Integer value1 = list.update(0,0);
        System.out.println(list);
        System.out.println(value1);
        Integer value2 = list.update(100,4);
        System.out.println(list);
        System.out.println(value2);
    }
}