package com.coding.basic;
import java.util.Iterator;
/**
* @author Scholar
* @Time：2017年3月6日 下午9:45:54
* @version 1.0
*/
public class LinkedList implements List {
private Node head;
private int size;
public boolean add(Object o){
addLast(o);
return true;
}
public void add(int index , Object o){
checkPositionIndex(index);
if (index == 0) {
addFirst(o);
} else if (index == size) {
addLast(o);
} else {
Node x = head;
for (int i = 0; i < index - 2; i++) {
x = x.next;
}
Node temp = new Node(o,x.next);
x.next = temp;
}
size++;
}
public Object get(int index){
checkElementIndex(index);
Node x = head;
for (int i = 0; i < index; i++) {
x = x.next;
}
return x.data;
}
@SuppressWarnings("unused")
public Object remove(int index){
checkElementIndex(index);
Object element = null;
if (index == 0) {
Node removeNode = head;
head = head.next;
element = removeNode.data;
removeNode = null;
} else {
checkElementIndex(index - 1);
Node x = head;
for (int i = 0; i < index - 1; i++) {
x = x.next;
}
Node removeNode = x.next;
x.next = removeNode.next;
element = removeNode.data;
removeNode = null;
}
size--;
return element;
}
public int size(){
return size;
}
public void addFirst(Object o){
Node temp = head;
Node newNode = new Node(o,temp);
head = newNode;
size++;
}
public void addLast(Object o){
Node temp = new Node(o, null);
if (size == 0) {
head = temp;
} else {
Node x = head;
while (x.next != null) {
x = x.next;
}
x.next = temp;
}
size++;
}
public Object removeFirst(){
Object element = null;
if (size != 0) {
element = head.data;
head.data = null;
Node next = head.next;
head.next = null;
head = next;
size--;
}
return element;
}
public Object removeLast(){
Object element = null;
if (size != 0) {
if (head.next == null) {
element = head.data;
head.data = null;
} else {
Node x = head;
for (int i = 0; i < size - 2; i++) {
x = x.next;
}
Node removeNode = x.next;
x.next = null;
element = removeNode.data;
removeNode = null;
}
size--;
}
return element;
}
public Iterator<?> iterator(){
return new LinkedListIterator();
}
//检查下标是否合法
private void checkElementIndex(int index){
if (!isElementIndex(index)) {
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+size);
}
}
@SuppressWarnings("unused")
private void checkPositionIndex(int index){
if (!isPositionIndex(index)) {
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+size);
}
}
//检查该参数是否为现有元素的索引。
private boolean isElementIndex(int index) {
return index >= 0 && index < size;
}
//检查参数是否是迭代器或添加操作的有效位置的索引
private boolean isPositionIndex(int index) {
return index >= 0 && index <= size;
}
@SuppressWarnings("unused")
private static class Node{
Object data;
Node next;
Node(Object data, Node next){
this.data = data;
this.next = next;
}
}
private class LinkedListIterator implements Iterator<Object>{
private Node currentNode = head;
private int nextIndex = 0;//参考源码中的写法
@Override
public Object next() {
Object data = currentNode.data;
currentNode = currentNode.next;
nextIndex ++;
return data;
}
@Override
public boolean hasNext() {
return nextIndex != 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(){
if (head!=null) {
//上一结点
Node pre=head;
//当前结点
Node cur=head.next;
//用于存储下一节点
Node tem;
//cur==null 即尾结点
while(cur!=null){
//下一节点存入临时结点
tem=cur.next;
//将当前结点指针指向上一节点
cur.next = pre;
//移动指针
pre=cur;
cur=tem;
}
head.next = null;
}
//reverse(head);
}
private Node reverse(Node first) {
// first看作是前一结点，first.next是当前结点，reHead是反转后新链表的头结点
if (first == null || first.next == null) {
return head;// 若为空链或者当前结点在尾结点，则直接还回
}
Node reHead = reverse(first.next);// 先反转后续节点head.getNext()
first.next.next = first;// 将当前结点的指针域指向前一结点
first.next = null;// 前一结点的指针域令为null;
return reHead;// 反转后新链表的头结点
}
/**
* 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 removeLength = size()/2;
for (int i = 0; i < removeLength; 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 index, int length){
for (int i = 0; i < length; i++) {
this.remove(index);
}
}
/**
* 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[] result = new int[list.size()];
Iterator iterator = list.iterator();
int offset = 0;
while (iterator.hasNext()) {
int temp = (int) this.get((int)iterator.next());
result[offset++] = temp;
}
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list中出现的元素
* @param list
*/
public void subtract(LinkedList list){
Iterator iterator = list.iterator();
while (iterator.hasNext()) {
int temp = (int) iterator.next();
Node x = head;
Node p = null;
while (x.next != null) {
if ((int)x.data > temp) {
break;
}
if((int)x.data == temp){
if (p == null) {
removeFirst();
x = head;
} else {
p.next = x.next;
}
}
p = x;
x = x.next;
}
}
}
/**
* 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 p = head;
while(p.next != null){
Node x = p;
while (x.next != null) {
if(x.next.data == p.data){
x.next=x.next.next;
}
x=x.next;
}
p = p.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){
Node p = head;
int i = (int)p.data;
if (i > min && i < max) {
while ((int)p.data > min) {
if ((int)p.data >= max) {
break;
}
removeFirst();
p = head;
}
} else {
while (p.next != null) {
int temp = (int) p.next.data;
if (temp >= max) {
break;
}
if (temp > min) {
p.next=p.next.next;
}
p = p.next;
}
}
}
/**
* 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){
return null;
}
}