package com.pxshuo.se03.basic;
import com.pxshuo.se01.basic.Iterator;
public class LinkedList implements List {
private Node head;
private Node last;
private int size = 0;
private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+size;
}
private boolean isElementIndex(int index) {
return index >= 0 && index < size;
}
private void checkElementIndex(int index) {
if (!isElementIndex(index))
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
private boolean isPositionIndex(int index) {
return index >= 0 && index <= size;
}
private void checkPositionIndex(int index) {
if (!isPositionIndex(index))
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
/**
* 获取一个节点,不进行范围检查
* @param index 位置
*/
private Node getNode(int index){
Node node = head;
for (int i = 0; i < index; i++) {
node = node.next;
}
return node;
}
/**
* 添加一个节点
* @param o
*/
public void add(Object o){
Node node = new Node(o);
Node l = last;
last = node;
if (head == null) {
head = node;
}
else{
l.next = last;
}
size ++;
}
/**
* 在某个位置进行插入
* @param index 位置
* @param o 插入的元素
*/
public void add(int index , Object o){
checkPositionIndex(index);
if (size == index) {
add(o);
}
else if (0 == index){
addFirst(o);
}
else {
Node node = new Node(o);
Node preNode = getNode(index - 1);
node.next = preNode.next;
preNode.next = node;
size++;
}
}
/**
* 获取一个节点
* @param index 位置
*/
public Object get(int index){
checkElementIndex(index);
return getNode(index).data;
}
public Object remove(int index){
checkElementIndex(index);
Object data = null;
if (index == 0) {
data = removeFirst();
}
else if(index == size) {
data = removeLast();
}
else {
Node pre = getNode(index - 1);
data = pre.next.data;
pre.next = pre.next.next;
size --;
}
return data;
}
public int size(){
return size;
}
/**
* 添加第一个元素
* @param o
*/
public void addFirst(Object o){
if (head == null) {
add(o);
return;
}
Node node = new Node(o);
node.next = head;
head = node;
size ++;
}
/**
* 添加最后的元素
* @param o
*/
public void addLast(Object o){
add(o);
}
/**
* 移除最初元素
* @return
*/
public Object removeFirst(){
checkElementIndex(0);//检查首位是否有元素
if (head == last) {
last = null;
}
Object data = head.data;
head = head.next;
size --;
return data;
}
/**
* 移除最后的元素
* @return
*/
public Object removeLast(){
checkElementIndex(0);//检查首位是否有元素
if (head == last) {
return removeFirst();
}
Object data = last.data;
last = getNode(size - 2);
last.next = null;
return data;
}
public Iterator iterator(){
return new LinkedListIterator();
}
public void display() {
Node cur = head;
int i = 0;
while(cur != null && i < 1000)
{
System.out.println(i + ":" + cur.data.toString());
cur = cur.next;
}
}
public String getResult() {
Node cur = head;
int i = 0;
String result = "";
while(cur != null && i < 1000)
{
result += cur.data.toString();
cur = cur.next;
if (cur != null) {
result += ",";
}
}
return result;
}
private static class Node{
Object data;
Node next;
public Node(Object o){
data = o;
}
}
private class LinkedListIterator implements Iterator{
Node position = null;
public LinkedListIterator() {
this.position = head;
}
@Override
public boolean hasNext() {
if (position == null) {
return false;
}
return true;
}
@Override
public Object next() {
Object data = position.data;
position = position.next;
return data;
}
}
/**
* 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(){
checkElementIndex(0);
if (size == 1) {
return;
}
last = head;
Node pre = null;
Node next = null;
while(head.next != null){
next = head.next;
head.next = pre;
pre = head;
head = next;
}
head.next = pre;
}
/**
* 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(){
if (size < 2) {
head = null;
last = null;
size = 0;
}
int half = size/2;
Node halfPre = getNode(half - 1);
head = halfPre.next;
halfPre.next = null;
size = size - half;
}
/**
* 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 (length < 1) {
return;
}
checkElementIndex(i);
checkElementIndex(i + length - 1);
Node pre = null;//删除元素的前一个
Node nextPre = getNode(i + length - 1);//删除元素的最后一个
if (i != 0) {
pre = getNode(i - 1);
}
if (pre != null) {
pre.next = nextPre.next;
}
else {
head = nextPre.next;
}
if (nextPre.next == null) {
last = pre;
}
nextPre = null;
size -= length;
}
/**
* 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[] listResult = new int[list.size];
int i = 0;
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
int index = Integer.parseInt(iterator.next().toString());
listResult[i] = Integer.parseInt(get(index).toString());
i ++;
}
return listResult;
}
/**
* 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){
int index = 0;
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
Object del = iterator.next();
for (index = 0;index < size;index ++) {
if (((String)get(index)).equals((String)del)) {
remove(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(){
checkElementIndex(0);
Node cur = head;
while(cur.next != null){
String curData = (String)(cur.data);
String nextData = (String)(cur.next.data);
if (curData.equals(nextData)) {
size --;
if (cur.next == last) {
cur.next = null;
last = cur;
}else {
cur.next = cur.next.next;
}
}
else {
cur = cur.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){
checkElementIndex(0);
Node minNode = null;//删除的前一个节点
Node maxNode = null;
Node cur = head;
Node pre = null;
int delSize = 0;
while(cur != null){
int curVal = Integer.parseInt((String)(cur.data));
if (minNode == null && delSize == 0) {
if (curVal > min) {//开始删除
minNode = pre;
delSize ++;
}
}
if (delSize != 0) {
if (curVal > max) {//结束删除
maxNode = cur;
break;//跳出循环
}
else {
delSize ++;
}
}
pre = cur;
cur = cur.next;
}
//进行删除
if (delSize - 1 == size) {//删除全部
head = null;
last = null;
size = 0;
return;
}
else if (delSize == 0) {//没有删除任务
return;
}
else if (minNode == null) {//从头部开始删除
head = maxNode;
}
else if (maxNode == null) {//删除尾部
last = minNode;
last.next = null;
}
else {//删除中间部分
minNode.next = maxNode;
}
size -= delSize - 1;
}
/**
* 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){
LinkedList result = new LinkedList();
Node cur = head;
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
Object data = iterator.next();
int dataNum = Integer.parseInt((String)data);
while(cur != null){
int curData = Integer.parseInt((String)(cur.data));
if(curData == dataNum){
result.add(data);
break;
}
else if(dataNum < curData){
break;
}
cur = cur.next;
}
}
return result;
}
}