package com.coding.basic;
import java.util.Arrays;
public class LinkedList implements List {
private Node head;
private Node last;
private int size = 0;
public void add(Object o) {
if (head == null) {
head = new Node(o, null);
size++;
return;
}
Node n = new Node(o, null);
if (last == null) {
last = n;
head.next = last;
}
last.next = n;
last = n;
size++;
}
public void add(int index, Object o) {
if (index < 0 || index > size) {
System.out.println("linkedList.add: index < 0 || index > size");
return;
}
if (index == size) {
add(o);
return;
}
if (index == 0) {
addFirst(o);
return;
}
Node pre = head;
for (int i = 1; i < index; i++) {
pre = pre.next;
}
Node post = pre.next;
Node n = new Node(o, post);
pre.next = n;
size++;
}
public Object get(int index) {
return this.getNode(index).data;
}
public Node getNode(int index) {
if (index == 0) {
return this.head;
}
Node n = head;
for (int i = 1; i <= index; i++) {
n = n.next;
}
return n;
}
public Object remove(int index) {
if (index < 0 || index >= size) {
System.out.println("remove :index < 0 || index >= size");
return null;
}
if (index == 0) {
return removeFirst();
}
if (index == size - 1) {
return removeLast();
}
Node pre = head;
for (int i = 1; i < index; i++) {
pre = pre.next;
}
Node n = pre.next;
Node post = n.next;
n.next = null;
pre.next = post;
size--;
return n.data;
}
public int size() {
return size;
}
public void addFirst(Object o) {
Node n = new Node(o, head);
head = n;
size++;
return;
}
public void addLast(Object o) {
Node n = new Node(o, null);
last.next = n;
last = n;
size++;
return;
}
public Object removeFirst() {
Object o = head.data;
Node n = head.next;
head.next = null;
head = n;
size--;
return o;
}
public Object removeLast() {
Node preLast = head;
for (int i = 1; i < size; i++) {
preLast = preLast.next;
}
preLast.next = null;
Object o = last.data;
last = preLast;
size--;
return o;
}
public Iterator iterator() {
return new Iterator() {
int cusor = 0;
Node current = head;
@Override
public Object next() {
if (!hasNext()) {
System.out.println("next : !hasNext");
return null;
}
Object o = current.data;
current = current.next;
cusor++;
return o;
}
@Override
public boolean hasNext() {
return cusor < size;
}
};
}
private static class Node {
Object data;
Node next;
public Node(Object data, Node next) {
this.data = data;
this.next = next;
}
}
/**
* 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 (this.size() < 2) {
return;
}
for (int i = this.size() - 1; i > 0; i--) {
this.getNode(i).next = this.getNode(i - 1);
}
Node temp = this.last;
this.last = this.head;
this.head = temp;
}
/**
* 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 delSize = this.size() >> 1;
Node temp = this.getNode(delSize);// getNode(index)
// 方法依赖前面元素的next指针,所以此语句在for循环前面
for (int i = delSize - 1; i >= 0; i--) {
this.getNode(i).next = null;
this.size--;
}
this.head = temp;// 由于getNode(index) 方法如果index传入0
// ,返回head,所以此语句要方法for循环后面
}
/**
* 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 || this.size() < i + length) {
return;
}
if (i == 0 && this.size() == length) {
this.head = null;
this.size = 0;
this.last = null;
return;
}
Node iNode = this.getNode(i - 1);
Node pre = this.getNode(i + length - 1);
Node post = this.getNode(i + length);
pre.next = null;
iNode.next = post;
this.size = this.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) {
Iterator select = list.iterator();
Iterator original = this.iterator();
int[] result = new int[this.size()];
int cosur = 0;
while (select.hasNext()) {
int s = (int) select.next();
String selStr = String.valueOf(s);
while (original.hasNext()) {
int o = (int) original.next();
String oriStr = String.valueOf(o);
if (oriStr.contains(selStr)) {
result[0] = o;
cosur++;
break;
}
}
}
return Arrays.copyOf(result, cosur - 1);
}
/**
* 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 select = list.iterator();
Iterator original = this.iterator();
int[] result = new int[this.size()];
int cosur = 0;
while (select.hasNext()) {
int sel = (int) select.next();
while (original.hasNext()) {
int ori = (int) original.next();
cosur++;
if (ori == sel) {
remove(cosur);
}
}
}
}
/**
* 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;
}
for (int i = this.size(); i > 0; i--) {
if ((int) get(i) == (int) get(i - 1)) {
this.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) {
int minIndex = 0;
int maxIndex = 0;
for (int i = this.size(); i > 0; i--) {
if (max > (int) get(i)) {
maxIndex = i;
}
}
for (int i = 0; i < maxIndex; i++) {
if (min < (int) get(i)) {
minIndex = i;
}
}
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) {
LinkedList result = new LinkedList();
Iterator select = list.iterator();
Iterator original = this.iterator();
int sel = (int) select.next();
int ori = (int) original.next();
while (original.hasNext() && select.hasNext()) {
if (ori == sel) {
result.add(ori);
} else if (ori < sel) {
ori = (int) original.next();
} else {
sel = (int) select.next();
}
}
return result;
}
}