package com.coding.basic;
public class LinkedList implements List {
private Node head;
private Node last;
private int size;
public LinkedList() {
}
public void add(Object obj) {
addLast(obj);
}
public void add(int index, Object o) {
if (index == size) {
addLast(o);
} else {
linkBefor(o, node(index));
}
}
public Object get(int index) {
// 双重循环链表 size>>1 判断距离哪边近
// 从第一个开始找
return node(index).data;
}
public Object remove(int index) {
return unlink(node(index));
}
public int size() {
return size;
}
public void addFirst(Object o) {
final Node f = head;
final Node newNode = new Node(null, o, f);
head = newNode;
if (f == null)
last = newNode;
else
f.prev = newNode;
size++;
}
private void addLast(Object obj) {
Node tempNode = last;
Node newNode = new Node(tempNode, obj, null);
last = newNode;
if (tempNode == null) {
head = newNode;
} else {
tempNode.next = newNode;
}
size++;
}
public Object removeFirst() {
Node h = head;
Object element = h.data;
Node next = h.next;
h.data = null;
h.next = null; // help GC
head = next;
if (next == null)
last = null;
else
next.prev = null;
size--;
return element;
}
public Object removeLast() {
Node l = last;
Object element = l.data;
Node prev = l.prev;
l.data = null;
l.prev = null;
last = prev;
if (prev == null)
head = null;
else
prev.next = null;
size--;
return element;
}
public Iterator iterator() {
return null;
}
private void linkBefor(Object o, Node node) {
Node pred = node.prev;
Node newNode = new Node(pred, o, node);
node.prev = newNode;
if (pred == null) {
head = newNode;
} else {
pred.next = newNode;
}
size++;
}
private Object unlink(Node node) {
Node prev = node.prev;
Object obj = node.data;
Node next = node.next;
if (prev == null) {
head = next;
} else {
node.prev = null;
prev.next = next;
}
if (next == null) {
last = prev;
} else {
next.prev = prev;
node.next = null;
}
node.data = null;
size--;
return obj;
}
Node node(int index) {
if (index < (size >> 1)) {
Node x = head;
for (int i = 0; i < index; i++) {
x = x.next;
}
return x;
} else {
Node x = last;
for (int i = size - 1; i > index; i--) {
x = x.prev;
}
return x;
}
}
private static class Node {
Object data;
Node prev;
Node next;
Node(Node prev, Object data, Node next) {
this.prev = prev;
this.next = next;
this.data = data;
}
}
/**
* 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() {
}
/**
* 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() {
}
/**
* 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) {
}
/**
* 假定当前链表和listB均包含已升序排列的整数 从当前链表中取出那些listB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) {
return null;
}
/**
* 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listB中出现的元素
*
* @param list
*/
public void subtract(LinkedList list) {
}
/**
* 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() {
}
/**
* 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) {
}
/**
* 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) {
return null;
}
}