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2.LinkedList
import java.util.NoSuchElementException;
import org.junit.Test;
public class LinkedList implements List {
private Node first;
private Node last;
private int size;
/**
* 头部添加节点方法
*/
private void linkFirst(Object o) {
final Node node = first;
final Node firstNode = new Node(o, node, null);
this.first = firstNode;
if (node == null) {
last = firstNode;
} else {
node.prev = firstNode;
}
size++;
}
/**
* 末端添加节点方法
*
* @param o
*/
private void linkLast(Object o) {
final Node node = last;
final Node lastNode = new Node(o, null, node);
last = lastNode;
if (node == null) {
first = lastNode;
} else {
node.next = lastNode;
}
size++;
}
/**
* 在链表末端添加节点
*/
public void add(Object o) {
if (o != null)
linkLast(o);
}
/**
* 在指定下标处添加节点
*/
public void add(int index, Object o) {
checkIndex(index);
Node befo = getNodeByIndex(index);
linkBefore(o, befo);
}
/**
* 根据下标获取节点
*/
public Object get(int index) {
checkIndex(index);
return getNodeByIndex(index).data;
}
/**
* 根据下标移除节点
*/
public Object remove(int index) {
checkIndex(index);
Node current = getNodeByIndex(index);
final Node node = current;
final Node prev = node.prev;
final Node next = node.next;
if (prev == null) {
first = next;
} else {
prev.next = next;
next.prev = prev;
current = null;
}
if (next == null) {
last = prev;
} else {
prev.next = next;
next.prev = prev;
current = null;
}
size--;
return node.data;
}
/**
* 返回链表长度
*/
public int size() {
return size;
}
/**
* 在链表头添加节点
*
* @param o
*/
public void addFirst(Object o) {
linkFirst(o);
}
/**
* 在链表最后添加节点
*
* @param o
*/
public void addLast(Object o) {
linkLast(o);
}
/**
* 移除链表首个元素
*
* @return
*/
public Object removeFirst() {
Node node = first;
if (node == null)
throw new NoSuchElementException();
else {
Node next = node.next;
if (next == null)
first = null;
else {
first = next;
first.prev = null;
}
}
size--;
return node.data;
}
/**
* 移除链表最后一个元素
*
* @return
*/
public Object removeLast() {
Node node = last;
if (last == null)
throw new NoSuchElementException();
else {
Node prev = node.prev;
if (prev == null)
last = null;
else {
last = prev;
last.next = null;
}
}
size--;
return node.data;
}
/**
* 迭代方法
*
* @return
*/
public Iterator iterator() {
return new Iter();
}
/**
* 在节点之前插入一个新的节点
*
* @param data
* @param befo
*/
private void linkBefore(Object data, Node befo) {
final Node prev = befo.prev;
final Node node = new Node(data, befo, prev);
befo.prev = node;
if (prev == null)
first = node;
else
prev.next = node;
size++;
}
/**
* 根据下标获取节点
*
* @param index
* @return
*/
private Node getNodeByIndex(int index) {
checkIndex(index);
Node node = first;
for (int x = 0; x < index; x++) {
node = node.next;
}
return node;
}
/**
* 检查下标是否越界
*
* @param index
*/
private void checkIndex(int index) {
// TODO Auto-generated method stub
if (index < 0 || index > size) {
throw new IndexOutOfBoundsException("链表下标越界");
}
}
/**
* 迭代器内部类
*
* @author Adminstater
*
*/
private class Iter implements Iterator {
private int nextIndex = 0;
@Override
public boolean hasNext() {
// TODO Auto-generated method stub
return nextIndex != size;
}
@Override
public Object next() {
// TODO Auto-generated method stub
int i = nextIndex++;
if (i > size - 1)
throw new IndexOutOfBoundsException();
return getNodeByIndex(i).data;
}
}
/**
* 节点内部类
*
* @author Adminstater
*
*/
private static class Node {
Object data;
Node next;
Node prev;
private Node(Object data, Node next, Node prev) {
this.data = data;
this.next = next;
this.prev = prev;
}
private Node() {
}
}
/*------------------------------------------------------单元测试----------------------------------------------------*/
/**
* 测试添加方法功能
*/
// add(Object o)
@Test
public void TestAddFunction() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println("添加完毕");
}
// add(int index,Object o)
@Test
public void TestAddIndexFunction() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
for (int x = 0; x < list.size(); x++) {
System.out.println(list.get(x));
}
list.add(3, 111);
System.out.println(list.get(3));
}
// addFirst(Object o)
@Test
public void TestAddFirstFunction() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println(list.get(0));
list.addFirst(20);
System.out.println(list.get(0));
}
// addLast(Object o)
@Test
public void TestAddLastFunction() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println(list.get(list.size() - 1));
list.addLast(111);
System.out.println(list.get(list.size() - 1));
}
/**
* remove方法测试
*/
// removeFirst()
@Test
public void TestRemoveFirst() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println(list.get(0));
list.removeFirst();
System.out.println(list.get(0));
}
// removeLast()
@Test
public void TestRemoveLast() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println(list.get(list.size() - 1));
list.removeLast();
System.out.println(list.get(list.size() - 1));
}
// remove(int index)
@Test
public void TestRemoveFunction() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
System.out.println(list.get(50));
list.remove(50);
System.out.println(list.get(50));
}
/**
* Iterator测试
*/
@Test
public void TestIterator() {
LinkedList list = new LinkedList();
for (int i = 0; i < 100; i++) {
list.add(i);
}
Iterator ite = list.iterator();
while (ite.hasNext()) {
System.out.println(ite.next());
}
}
public static void main(String[] args) {
java.util.LinkedList list = null;
}
}