package com.donaldy.basic;
import java.util.*;
/**
* Created by donal on 2017/3/9.
* single LinkedList
*/
public class LinkedList implements List {
private int size;
private Node head;
private Node last;
public void add(Object o) {
addLast(o);
}
public void addLast(Object o) {
final Node l = last;
final Node newNode = new Node(o, null);
last = newNode;
if (l == null)
head = newNode;
else
l.next = newNode;
size ++;
}
public void add(int index , Object o) {
makeSure(index);
if (index == 0){
addFirst(o);
}else {
final Node preNode = getPreNode(index);
final Node nextNode = preNode.next;
final Node newNode = new Node(o, nextNode);
preNode.next = newNode;
}
}
public void addFirst(Object o){
final Node h = head;
final Node newNode = new Node(o, head);
head = newNode;
if (h == null)
last = newNode;
size++;
}
private Node getPreNode(int index) {
Node preNode = head;
for (int i = 0 ; i != index - 1 && preNode != null; ++i) {
preNode = preNode.next;
}
return preNode;
}
private void makeSure(int index) {
if (index >= size || index < 0)
throw new IndexOutOfBoundsException();
}
public Object get(int index) {
Object targetData = null;
makeSure(index);
Iterator iterator = iterator();
for (int i = 0; iterator.hasNext(); ++i, iterator.next()) {
if (i == index) {
targetData = iterator.next();
break;
}
}
return targetData;
}
public Object remove(int index) {
if (size <= 0)
throw new IndexOutOfBoundsException();
makeSure(index);
Object oldData;
if (index == 0) {
oldData = removeFirst();
} else if (index == size - 1) {
oldData = removeLast();
} else {
final Node preNode = getPreNode(index);
final Node nextNode = preNode.next.next;
oldData = preNode.next.data;
preNode.next = nextNode;
size --;
}
return oldData;
}
public Object removeFirst() {
Object oldData;
final Node h = head.next;
oldData = head.data;
head = h;
size --;
return oldData;
}
public Object removeLast() {
Object oldData;
final Node l = getPreNode(size);
oldData = last.data;
last = l;
size --;
return oldData;
}
public int size(){
return size;
}
public Iterator iterator() {
return new LinkedListIterator();
}
private class LinkedListIterator implements Iterator{
private Node pointer = head;
private int nextIndex = 0;
@Override
public boolean hasNext() {
return nextIndex < size;
}
@Override
public Object next() {
if (!hasNext())
throw new NoSuchElementException();
Object nodeData = pointer.data;
pointer = pointer.next;
nextIndex ++;
return nodeData;
}
}
private static class Node {
Object data;
Node next;
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() {
Node node = last;
Node preNode = head;
last = head;
head = node;
node = preNode.next;
Node nextNode;
preNode.next = null;
while (node != null) {
nextNode = node.next;
node.next = preNode;
preNode = node;
node = nextNode;
}
}
/**
* 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 half = size / 2;
Node node = head;
while (half != 0 ) {
head = head.next;
node.next = null;
node = head;
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 (i + length != size)
makeSure(i + length);
Node node = head;
Node preNode = head;
if (i > 0) {
for (int j = 0; j < i; ++j) {
preNode = node;
node = node.next;
}
}
Node tempNode;
for (int j = 0; j < length; ++j) {
tempNode = node.next;
node.next = null;
node = tempNode;
size --;
}
if (i == 0) {
head = node;
} else {
preNode.next = node;
}
}
/**
* 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 array[] = new int[list.size()];
int index = 0;
int i = 0;
Iterator iterator = list.iterator();
while (iterator.hasNext()) {
i = (int)iterator.next();
makeSure(i);
array[index ++] = (int)get(i);
}
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
*
* (适用于list 是 List的真子集)
* @param list
*/
public void subtract(LinkedList list) {
Iterator iterator = list.iterator();
int index = 0;
Object element;
while (iterator.hasNext()) {
element = iterator.next();
for (int i = index; i < size; ++i) {
if (element == get(i)) {
index = i;
break;
}
}
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() {
Set set = new HashSet();
Object element;
int index = 0;
Node node = head;
while (node != null) {
element = node.data;
if (set.contains(element)) {
System.out.println("remove !");
remove(index);
}else {
set.add(element);
index++;
}
node = node.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 (max < min || max < 0 || min < 0)
throw new RuntimeException();
Node startNode, endNode, node, preNode;
startNode = head;
endNode = last;
node = head;
preNode = node;
int element;
boolean flagS = true, flagT = true;
while (node != null) {
element = (int) node.data;
if (element > min && flagS) {
startNode = node;
flagS = false;
}
if (element >= max && flagT) {
endNode = node;
flagT = false;
}
if (flagS)
preNode = node;
node = node.next;
}
if (head == startNode) {
head = endNode;
} else {
if (last == endNode) {
last = preNode;
preNode.next = null;
endNode = null;
} else {
preNode.next = endNode;
}
}
Node tempNode;
while (startNode != endNode) {
tempNode = startNode;
startNode = startNode.next;
tempNode.next = null;
size --;
}
}
/**
* 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 newLink = new LinkedList();
Iterator it1 = iterator();
Iterator it2 = list.iterator();
int element1 = (int)it1.next();
int element2 = (int)it2.next();
while (it1.hasNext() && it2.hasNext()) {
if (element1 < element2) {
newLink.add(element1);
element1 = (int) it1.next();
} else {
newLink.add(element2);
element2 = (int) it2.next();
}
}
while (it1.hasNext()) {
if (element1 == 0)
element1 = (int)it1.next();
newLink.add(element1);
element1 = 0;
}
while (it2.hasNext()) {
if (element2 == 0)
element2 = (int)it2.next();
newLink.add(element2);
element2 = 0;
}
if (element1 < element2)
newLink.add(element2);
else if (element2 < element1)
newLink.add(element1);
return newLink;
}
}