package week03.basic;
import java.util.Objects;
import week01.basic.Iterator;
import week01.basic.List;
public class MyLinkedList implements List {
private Node head;
private int size;
/**************************************** 第一次作业 ***************************************/
public void add(Object o) {
// 空链表
if (head == null) {
head = new Node();
head.data = o;
head.next = null;
} else {
Node p = head;
while (p.next != null) {
p = p.next;
}
Node target = new Node();
target.data = o;
target.next = null;
p.next = target;
}
size++;
}
public void add(int index, Object o) {
// index 是否合法
checkPositionIndex(index);
if (head == null) {
head = new Node();
head.data = o;
head.next = null;
} else {
if (index == 0) {
addFirst(o);
} else if (index == size) {
addLast(o);
} else {
Node p = new Node();
Node p1 = head;
for (int i = 0; i < index - 1; i++) {
p1 = p1.next;
}
p.data = o;
p.next = p1.next;
p1.next = p;
size++;
}
}
}
public Object get(int index) {
checkElementIndex(index);
Node p = head;
for (int i = 0; i < index; i++) {
p = p.next;
}
return p.data;
}
public Object remove(int index) {
checkElementRemove();
checkElementIndex(index);
Object removeObject = null;
if (index == 0) {
removeObject = removeFirst();
} else if (index == (size - 1)) {
removeObject = removeLast();
} else {
Node p = head;
for (int i = 1; i < index; i++) {
p = p.next;
}
removeObject = p.next.data;
p.next = p.next.next;
size--;
}
return removeObject;
}
public int size() {
return size;
}
public void addFirst(Object o) {
if (head == null) {
head = new Node();
head.data = o;
head.next = null;
} else {
Node p = new Node();
p.data = o;
p.next = head;
head = p;
}
size++;
}
public void addLast(Object o) {
add(o);
}
public Object removeFirst() {
checkElementRemove();
Object removeObject = head.data;
head = head.next;
size--;
return removeObject;
}
public Object removeLast() {
checkElementRemove();
Object removeObject = null;
if (size == 1) {
removeObject = head.data;
head = head.next;
} else {
Node p = head;
for (int i = 0; i < size; i++) {
if (p.next.next == null) {
removeObject = p.next.data;
p.next = null;
break;
} else {
p = p.next;
}
}
}
size--;
return removeObject;
}
private boolean isEmpty() {
return size == 0;
}
private void checkElementRemove() {
if (isEmpty()) {
throw new NullPointerException("The list is empty.");
}
}
private void checkElementIndex(int index) {
if (!isElementIndex(index)) {
throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
}
}
private boolean isElementIndex(int index) {
return index >= 0 && index < size;
}
private void checkPositionIndex(int index) {
if (!isPositionIndex(index)) {
throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
}
}
private boolean isPositionIndex(int index) {
return index >= 0 && index <= size;
}
public Iterator iterator() {
return new MyLinkedListIterator(this);
}
private class MyLinkedListIterator implements Iterator {
private MyLinkedList list = null;
private int position = 0;
private MyLinkedListIterator(MyLinkedList list) {
this.list = list;
}
@Override
public boolean hasNext() {
if ((position + 1) > size()) {
return false;
}
return true;
}
@Override
public Object next() {
return list.get(position++);
}
}
private static class Node {
Object data;
Node next;
}
/****************************************
* 第三次作业 ***************************************
*
*
* /** 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 p = this.head.next;
head.next = null;
while (p != null) {
addFirst(p.data);
size--;
p = p.next;
}
}
/**
* 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 removeSize = size / 2;
for (int i = 0; i < removeSize; i++) {
head = head.next;
}
}
/**
* 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) {
for (int index = 0; index < length; index++) {
remove(i);
}
}
/**
* 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(MyLinkedList list) {
int[] array = new int[list.size];
int i = 0;
for (Node head = list.head; head != null; head = head.next) {
array[i++] = (int) this.get((int) head.data);
}
return array;
}
/**
* 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(MyLinkedList list) {
for (Iterator iterator = list.iterator(); iterator.hasNext();) {
Object data = iterator.next();
Node p = head;
int index = 0;
while (p != null) {
if (Objects.equals(p.data, data)) {
this.remove(index);
break;
} else {
p = p.next;
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() {
if (size == 0 || size == 1) {
return;
}
Node p1 = head;
Node p2 = head.next;
while (p1 != null && p2 != null) {
if (Objects.equals(p1.data, p2.data)) {
p2 = p2.next;
p1.next = p2;
size--;
} else {
p1 = p2;
p2 = p2.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 p1 = head;
Node p2 = head;
while ((int) p2.data < max) {
if ((int) p1.next.data <= min) {
p1 = p1.next;
}
if ((int) p2.data < max) {
p2 = p2.next;
}
}
p1.next = p2;
}
/**
* 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 MyLinkedList intersection(MyLinkedList list) {
MyLinkedList rsList = new MyLinkedList();
Node p1 = this.head, p2 = list.head;
while (p1 != null && p2 != null) {
if (Objects.equals(p1.data, p2.data)) {
rsList.add(p1.data);
p1 = p1.next;
p2 = p2.next;
} else if ((int) p1.data > (int) p2.data) {
p2 = p2.next;
} else {
p1 = p1.next;
}
}
return rsList;
}
@Override
public String toString() {
String elementStr = "";
Node p = head;
while (p != null) {
elementStr += p.data + ",";
p = p.next;
}
return "MyLinkedList: { size=" + size + ", elementData=" + "["
+ elementStr.substring(0, elementStr.length() - 1) + "]" + " }";
}
}