package com.coderising.data;
import java.util.Arrays;
import java.util.NoSuchElementException;
public class LinkedList implements List {
private Node head;
private int size;
public LinkedList(){
size = 0;
head = null;
}
public void add(Object o){
Node node = new Node(o);
if(head == null){
head = node;
}else{
//p为游标 从头遍历到尾
Node p = head;
while(p.next != null){
p = p.next;
}
p.next = node;
}
size++;
}
public void add(int index , Object o){
//判断不为空链表
if(head != null){
Node p = head;
int k = 0;
//扫描单链表查找第index-1个节点
while(k < index-1 && p.next != null){
k++;
p = p.next;
}
//判断是否找到第index-1个节点
if(p != null){
Node node = new Node(o);
node.next = p.next;
p.next = node;
}
size++;
}
}
public Object get(int index){
if(index <0 || index >= size){
throw new IndexOutOfBoundsException();
}else{
Node p = head;
int k = 0;
while(k < index && p.next != null){
k++;
p = p.next;
}
return p.data;
}
}
public Object remove(int index){
if(index <0 || index >= size){
throw new IndexOutOfBoundsException();
}else{
if(head != null){
int k = 0;
Node p = head;
while(k < index-1 && p!=null){
k++;
p = p.next;
}
Node pn = p.next;
if(pn != null){
p.next = pn.next;
size--;
return pn.data;
}
}
}
return null;
}
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 node = new Node(o);
if(head == null){
head = node;
}else{
Node p = head;
while(p.next != null){
p = p.next;
}
p.next = node;
}
size++;
}
public Object removeFirst(){
if(head == null){
throw new NoSuchElementException();
}
Node node = head;
head = node.next;
size--;
return node.data;
}
public Object removeLast(){
if(head == null){
throw new NoSuchElementException();
}else{
Node p = head;
int k = 0;
while(k < size-1 && p.next != null){
k++;
p = p.next;
}
Node last = p.next;
p.next = null;
size--;
return last.data;
}
}
private static class Node{
Object data;
Node next;
private Node(Object o){
this.data = o;
this.next = null;
}
}
/**
* 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(null == head || null == head.next){
return;
}
else{
Node pre = head;
Node cur = head.next;
Node next;
while(cur != null){
next = cur.next;
cur.next = pre;
pre = cur;
cur = next;
}
head.next = null;
head = 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(){
int num = size/2;
for (int i = 0; i < num; 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 || i >= size){
throw new IndexOutOfBoundsException();
}else{
int len = size-i>=length ? length :size-i;
int k = 0;
while(k < len){
remove(i);
k++;
}
}
}
/**
* 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[] arr = new int[list.size()];
for (int i = 0; i < list.size(); i++) {
arr[i] = (int) this.get((int) list.get(i));
}
return arr;
}
/**
* 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 < list.size(); i++) {
this.remove(list.get(i));
}
}
/**
* 传入数据删除节点
* @param obj
*/
public void remove(Object obj){
if(head==null){
throw new RuntimeException("LinkedList is empty!");
}
//如果要删除的结点是第一个，则把下一个结点赋值给第一个结点
if(head.data==obj){
head=head.next;
size--;
}else{
Node pre=head; //上一节点
Node cur=head.next; //当前结点
while(cur!=null){
if(cur.data.equals(obj)){
pre.next=cur.next;
size--;
}
pre=pre.next;
cur=cur.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(){
if(head == null){
throw new RuntimeException("LinkedList is empty!");
}else{
Node pre = head;
Node cur = head;
while(cur.next != null){
cur = cur.next;
Object data = pre.data;
while(cur.data == data){
if(cur.next == null){
pre.next = null;
break;
}
pre.next = cur.next;
size--;
cur =cur.next;
if(cur == null){
break;
}
}
pre = pre.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(head == null){
throw new RuntimeException("LinkedList is empty!");
}else{
Node q = head;
Node p = head.next;
while(p!=null){
if((int)p.data>min && (int)p.data<max){
q.next=p.next;
size--;
p=q;
p=p.next;
}
else{
q=p;
p=p.next;
q=q.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){
LinkedList linkedList = new LinkedList();
intersection(linkedList,this.head, list.head);
return linkedList;
}
private void intersection(LinkedList linkedList, Node node1,Node node2){
if(node1 ==null && node2 == null){
}else if(node1 == null){
traverse(linkedList, node2);
}else if(node2 == null){
traverse(linkedList, node1);
}else{
if((int)node1.data < (int)node2.data){
linkedList.add(node1.data);
intersection(linkedList,node1.next,node2);
}else{
linkedList.add(node2.data);
intersection(linkedList,node1, node2.next);
}
}
}
private void traverse(LinkedList linkedList, Node node) {
while(node != null){
linkedList.add(node.data);
node = node.next;
}
}
public static void main(String[] args) {
LinkedList linkedList = new LinkedList();
linkedList.add(11);
linkedList.add(101);
linkedList.add(201);
linkedList.add(301);
linkedList.add(401);
linkedList.add(501);
linkedList.add(601);
linkedList.add(701);
LinkedList list = new LinkedList();
list.add(1);
list.add(3);
list.add(4);
list.add(6);
System.out.println(Arrays.toString(linkedList.getElements(list)));
}
}