public class LinkedList implements List {
private Node head;
private int size ;
private Node current = head;
public LinkedList() {
head = null;
size = 0;
}
public void add(Object o){
Node newNode = new Node();
newNode.data = o;
if (current.next == null)
{
current.next = newNode;
}
while (current.next != null){
current = current.next;
}
current.next = newNode;
size++;
}
public void add(int index , Object o){
Node newNode = new Node();
newNode.data = o;
if (index < 0 || index > size) {
throw new IndexOutOfBoundsException();
}
for (int i = 0; i < index - 2; i++) {
current = current.next;
}
newNode.next = current.next;
current.next = newNode;
size++;
}
public Object get(int index){
if (index < 0 || index > size) {
throw new IndexOutOfBoundsException();
} else if (index == 0) {
return head;
}
for (int i = 0;i<index - 1; i++) {
current = current.next;
}
return current;
}
public Object remove(int index){
for (int i = 1; i <= index; i++) {
if (i == index - 1) {
current.next = current.next.next;
size--;
} else {
current = current.next;
}
}
return null;
}
public int size(){
return size;
}
public void addFirst(Object o){
Node newHead = new Node();
newHead.data = o;
newHead.next = head;
head = newHead;
size++;
}
public void addLast(Object o){
Node newNode = new Node();
newNode.data = o;
while (current.next != null){
current = current.next;
}
current.next = newNode;
size++;
}
public Object removeFirst(){
Node removeHead = head;
head.next = head.next.next;
size--;
return removeHead;
}
public Object removeLast(){
Node theNext = current.next;
Node oldLast;
while(theNext.next != null) {
current = theNext;
theNext = theNext.next;
}
oldLast=current.next;
current.next = theNext.next;
size--;
return oldLast;
}
public Iterator iterator(){
return new LinkedListIterator();
}
public Object head() {
return head;
}
private class LinkedListIterator implements Iterator {
@Override
public boolean hasNext() {
return current.next!=null;
}
@Override
public Object next() {
Node data = (Node) current.data;
current.next = current.next.next;
return data;
}
}
private static class Node{
Object data;
Node next;
}
/**
* 把该链表逆置
* 例如链表为 3->7->10 , 逆置后变为 10->7->3
*/
public void reverse(){
Node p = null;
while (head != null) {
Node next = head.next;
head.next = p;
p = head;
head = next;
}
}
/**
* 删除一个单链表的前半部分
* 例如：list = 2->5->7->8 , 删除以后的值为 7->8
* 如果list = 2->5->7->8->10 ,删除后的值为7,8,10
*/
public void removeFirstHalf(){
for (int i = 0;i<size()/2;i++) {
removeFirst();
}
}
/**
* 从第i个元素开始， 删除length 个元素 ， 注意i从0开始
* @param i
* @param length
*/
public void remove(int i, int length){
if (i < 0) {
return;
}
for (int j=0;j<length;j++) {
remove(i);
}
}
/**
* 假定当前链表和list均包含已升序排列的整数
* 从当前链表中取出那些list所指定的元素
* 例如当前链表 = 11->101->201->301->401->501->601->701
* listB = 1->3->4->6
* 返回的结果应该是[101,301,401,601]
* @param list
*/
public int[] getElements(LinkedList list){
int[] newList = new int[list.size()];
for (int i=0;i<list.size();i++) {
newList[i]= (int) get((Integer) list.get(i));
}
return newList ;
}
/**
* 已知链表中的元素以值递增有序排列，并以单链表作存储结构。
* 从当前链表中中删除在list中出现的元素
* @param list
*/
public void subtract(LinkedList list){
for (int i=0;i<size();i++) {
for (int j=0;j<list.size();j++) {
while (current != list.current) {
list.current = list.current.next;
}
list.remove(j);
}
current = current.next;
}
intersection(list);
}
/**
* 已知当前链表中的元素以值递增有序排列，并以单链表作存储结构。
* 删除表中所有值相同的多余元素（使得操作后的线性表中所有元素的值均不相同）
*/
public void removeDuplicateValues(){
Node next = head.next;
for (int i=0;i<size();i++) {
if (current.data == next.data) {
remove(i);
current = current.next;
next = next.next;
}
}
}
/**
* 已知链表中的元素以值递增有序排列，并以单链表作存储结构。
* 试写一高效的算法，删除表中所有值大于min且小于max的元素（若表中存在这样的元素）
* @param min
* @param max
*/
public void removeRange(int min, int max){
if (min < max) {
return;
}
for (int i=0;i<size();i++) {
if ((int) get(i) > min && (int) get(i) < max) {
remove(i);
}
}
}
/**
* 假设当前链表和参数list指定的链表均以元素依值递增有序排列（同一表中的元素值各不相同）
* 现要求生成新链表C，其元素为当前链表和list中元素的交集，且表C中的元素有依值递增有序排列
* @param list
*/
public LinkedList intersection( LinkedList list){
if (list.size() == 0) {
return null;
}
LinkedList newList = new LinkedList();
this.head = list.head;
Node temp;
//确定新的头结点
if((int)this.head.data <= (int)list.head.data){
head = this.head;
temp = this.head;
this.head = this.head.next;
}else{
head = list.head;
temp = list.head;
list.head = list.head.next;
}
//合并
while(this.head != null && list.head!=null){
if((int)this.head.data <= (int)list.head.data){
temp.next = this.head;
temp = temp.next;
this.head = this.head.next;
}else{
temp.next = list.head;
temp = temp.next;
list.head = list.head.next;
}
}
//合并剩余的元素
if(this.head != null){
temp.next = this.head;
}
if(list.head != null){
temp.next = list.head;;
}
return newList;
}
}