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 <E>
*/
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;
7ff7
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(
8000
));
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
8000
(value1);
Integer value2 = list.update(100,4);
System.out.println(list);
System.out.println(value2);
}
}