package week1_0226;
import java.util.NoSuchElementException;
public class LinkedList implements List {
private Node head;
private int size = 0;
public void add(Object o){
if (head == null) {
head = new Node(o);
} else {
//遍历到链表的尾部
Node tail = head;
while (tail.next != null) {
tail = tail.next;
}
Node node = new Node(o);
tail.next = node;
}
size ++;
}
public void add(int index , Object o){
rangeCheckForAdd(index);
if (index ==0) {
Node node = new Node(o);
node.next = head;
head = node;
} else {
Node preHead = head;
for (int i = 0; i < index -1; i ++){
preHead = head.next;
}
Node node = new Node(o);
node.next = preHead.next;
preHead.next = node;
}
}
public Object get(int index){
rangeCheck(index);
Node dest = head;
for (int i = 0; i< index; i++){
dest = dest.next;
}
return dest.data;
}
private void rangeCheck(int index){
if (index >= size || index <0){
throw new IndexOutOfBoundsException();
}
}
public Object remove(int index){
rangeCheck(index);
Node preDest = head;
for (int i = 0; i < index; i++){
preDest = preDest.next;
}
Node dest = preDest.next;
preDest.next = dest.next;
size --;
return dest;
}
public int size(){
return size;
}
public void addFirst(Object o){
Node node = new Node(o);
node.next = head;
head = node;
size ++;
}
public void addLast(Object o){
Node lastNode = head;
while (lastNode.next != null){
lastNode = lastNode.next;
}
Node node = new Node(o);
lastNode.next = node;
size++;
}
public Object removeFirst(){
if (head == null) {
throw new NoSuchElementException();
}
Node headTmp = head;
head = head.next;
size --;
return headTmp;
}
public Object removeLast(){
if (head == null) {
throw new NoSuchElementException();
}
if (head.next == null) {
Node dest = head;
head = null;
size --;
return dest;
}
Node preLastNode = head;
while(preLastNode.next.next != null) {
preLastNode = preLastNode.next;
}
Node dest = preLastNode.next;
preLastNode.next = null;
size --;
return dest;
}
public Iterator iterator(){
return null;
}
private void rangeCheckForAdd(int index){
if (index > size || index <0){
throw new IndexOutOfBoundsException();
}
}
private static class Node{
Object data;
Node next;
Node (Object data) {
this.data = data;
next = null;
}
}
/********************************************************************************************************************************************
*
* 第二次作业
*
*
*
*/
/**
* 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 reversedNode = null;
while (head != null) {
Node temp = head;
head = head.next;
temp.next = reversedNode;
reversedNode = temp;
}
head = reversedNode;
}
/**
* 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 newStartIndex = size/2;
for (int i =0;i<newStartIndex;i++){
head = head.next;
}
size = size - newStartIndex;
}
/**
* 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) {
throw new IllegalArgumentException();
}
if (i +length > size) {
length = size -i;
}
if (i == 0) {
for (int j = 0; j< length; j ++) {
head = head.next;
}
} else {
Node startNode = (Node) this.get(i);
Node endNode = (Node) this.get(i + length);
startNode.next = endNode;
}
size = 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){
checkList(list);
int[] dest = new int[list.size];
int arrayIndex = 0;
while (list.head != null) {
dest[arrayIndex] = (int)this.get((int)list.head.data);
++ arrayIndex;
list.head = list.head.next;
}
return dest;
}
private void checkList(LinkedList list) {
for (int i = 0; i <list.size; i++){
rangeCheck((int)list.get(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。
* 从当前链表中中删除在list中出现的元素
* @param list
*/
public void subtract(LinkedList list){
if (list == null || list.size == 0 || this.size == 0) {
return;
}
int index = 0;
int listIndex = 0;
Node temp = head;
while (true) {
if((int)temp.data <= (int)list.get(listIndex)){
index ++;
temp = temp.next;
} else if ((int)temp.data == (int)list.get(listIndex)) {
this.remove(index);
index ++;
listIndex ++;
} else if (index >= this.size || listIndex >= list.size) {
break;
}
}
}
/**
* 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(){
if (this.size == 0) {
return;
}
Node subHead = head;
Node subTail = head;
while(true) {
if (subTail == null) {
subHead.next = null;
break;
}
if ((int)subTail.data == (int)subHead.data) {
if (!(subTail ==subHead)){
this.size --;
}
subTail = subTail.next;
} else {
subHead.next = subTail;
subHead = subHead.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
*/
//一地bug。。。
public void removeRange(int min, int max){
if (this.size ==0) {
return;
}
if ((int)head.data > max) {
throw new IllegalArgumentException();
}
Node temp = head;
int index = 0;
int from = 0;
int to = 0;
while (temp != null) {
if ((int)temp.data <= min) {
temp = temp.next;
} else if ((int)temp.data > min && from == 0){
from = index;
}
if ((int)temp.data < max && from > 0) {
temp = temp.next;
} else if((int)temp.data > max && to == 0) {
to = index;
}
++ index;
}
if (to == 0) {
this.remove(from, this.size - from);
} else {
this.remove(from, to - from);
}
}
/**
* 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 (this.size ==0 || list.size == 0){
return null;
}
Node tempHead = head;
int listIndex = 0;
LinkedList newList = new LinkedList();
while (true) {
if(tempHead == null || list.size < listIndex) {
break;
}
if ((int)tempHead.data < (int)list.get(listIndex)){
tempHead = head.next;
} else if ((int)tempHead.data > (int)list.get(listIndex)){
listIndex ++;
} else if ((int)tempHead.data == (int)list.get(listIndex)){
newList.add(tempHead);
tempHead = tempHead.next;
++ listIndex;
}
}
return newList;
}
}