package basic;
public class LinkedList implements List{
private Node head;
private int size;
@Override
public void add(Object o) {
addLast(o);
}
@Override
public void add(int index, Object o) {
checkIndex(index);
Node current = findByIndex(index);
Node newNode = new Node(o, current);
if(index == 0){
head = newNode;
}else{
Node perv = findByIndex(index-1);
perv.next = newNode;
}
size++;
}
@Override
public Object get(int index) {
checkIndex(index + 1);
return findByIndex(index).data;
}
@Override
public Object remove(int index) {
Node remove = null;
checkIndex(index + 1);
Node next = findByIndex(index+1);
if(index == 0){
remove = head;
if(next == null){
head = null;
}else {
head = next;
}
}else{
Node perv = findByIndex(index-1);
remove = perv.next;
perv.next = next;
}
size--;
return remove.data;
}
@Override
public int size() {
return size;
}
public void addFirst(Object o){
head = new Node(o, head);
size++;
}
public void addLast(Object o){
Node nextNode = new Node(o, null);
if(head == null){
head = nextNode;
}else{
Node lastNode = findByIndex(size-1);
lastNode.next = nextNode;
}
size++;
}
public Object removeFirst(){
return remove(0);
}
public Object removeLast(){
return remove(size-1);
}
public Iterator iterator(){
return new LinkedListIterator();
}
private class LinkedListIterator implements Iterator{
int current = 0;
@Override
public boolean hasNext() {
return current < size;
}
@Override
public Object next() {
Node findByIndex = findByIndex(current);
if(current >= size){
throw new IndexOutOfBoundsException("current:"+current+" size:"+size);
}
current++;
return findByIndex.data;
}
}
private static class Node{
Object data;
Node next;
Node(Object data, Node next){
this.data = data;
this.next = next;
}
}
private Node findByIndex(int index){
Node lastNode = head;
for (int i = 0; i < index; i++) {
lastNode = lastNode.next;
}
return lastNode;
}
private void checkIndex(int index){
if(index > size || index < 0){
throw new IndexOutOfBoundsException("current:"+index+" size:"+size);
}
}
/**
* 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 current = this.head;
for (int i = 0; i < size-1; i++) {
removeFirst();
add(size - i, current.data);
current = current.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 ,删除以后的值为7,8,10
*
*/
public void removeFirstHalf(){
int total = size/2;
for (int i = 0; i < total; 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 || length < 0){
throw new IllegalArgumentException("参数异常");
}
if(i + length > size){
throw new IndexOutOfBoundsException();
}
for (int j = 0; j < length; j++) {
remove(i);
}
}
/**
* 假定当前链表和listB均包含已升序排列的整数
* 从当前链表中取出那些listB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){
if(list == null || list.head == null){
return new int[0];
}
int result[] = new int [list.size];
Iterator iterator = list.iterator();
int index = 0;
while(iterator.hasNext()){
int next = (int)iterator.next();
if(next < size){
result[index] = (int)this.get(next);
}
index++;
}
return result;
}
/**
* 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listB中出现的元素
* @param list
*/
public void subtract(LinkedList list){
if(list == null || list.head == null){
return;
}
Iterator iterator = list.iterator();
while(iterator.hasNext()){
Object next = iterator.next();
Iterator iteratorInner = this.iterator();
int index = 0;
while(iteratorInner.hasNext()){
if(next.equals(iteratorInner.next())){
this.remove(index);
break;
}
index++;
}
}
}
/**
* 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(){
for (int i = 0; i < size; i++) {
if(findByIndex(i).data == findByIndex(i+1).data){
remove(i);
}
}
}
/**
* 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){
throw new IllegalArgumentException("参数异常");
}
int minIndex = 0;
int maxIndex = 0;
boolean flag = true;
for (int i = 0; i < size; i++) {
int current = (int)get(i);
if(flag && current > min){
minIndex = i;
flag = false;
}else if(current >= max){
maxIndex = i;
break;
}else{
maxIndex = size;
}
}
remove(minIndex, maxIndex - minIndex);
}
/**
* 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 == null || list.head == null){
return null;
}
LinkedList linkedList = new LinkedList();
Iterator iterator = this.iterator();
while(iterator.hasNext()){
Object next = iterator.next();
Iterator iterator2 = list.iterator();
while(iterator2.hasNext()){
if(next.equals(iterator2.next())){
linkedList.add(next);
}
}
}
return linkedList;
}
}