package com.coding.basic;
import java.awt.Dimension;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.TreeSet;
public class LinkedList implements List {
private Node head;
private int size;
private Node last;
public void add(Object o) {
addLast(o);
}
public void add(int index, Object o) {
checkIndexRange(index);
if (index == 0) {
head = new Node(o, head);
last = head;
size++;
}else if(index==size()){
last.next = new Node(o, null);
last = last.next;
size++;
}else {
Node nd = getNode(index - 1);
nd.next = new Node(o, nd.next);
size++;
}
}
public Object get(int index) {
return getNode(index).data;
}
private Node getNode(int index) {
if (isLastIndex(index)){
return last;
}
Node nd = head;
for (int i = 0; i < index; i++) {
nd = nd.next;
}
return nd;
}
private boolean isLastIndex(int index) {
return index==size()-1;
}
public Object remove(int index) {
if (size == 0) {
throw new NoSuchElementException();
}
checkIndexRange(index);
if (index == 0) {
Object o = head.data;
head = head.next;
size--;
return o;
}else if(isLastIndex(index)){
Object o = last.data;
last=getNode(index-1);
last.next =null;
size--;
return o;
}else {
Node nd = getNode(index - 1);
Object o = nd.next.data;
nd.next = nd.next.next;
size--;
return o;
}
}
private void checkIndexRange(int index) {
if (index > size || index < 0) {
throw new IndexOutOfBoundsException("index超出数组界限?");
}
}
public int size() {
return size;
}
public void addFirst(Object o) {
add(0, o);
}
public void addLast(Object o) {
if (size == 0) {
addFirst(o);
} else {
add(size, o);
}
}
public Object removeFirst() {
return remove(0);
}
public Object removeLast() {
return remove(size - 1);
}
public Iterator iterator() {
return new MyIterator();
}
public void clear() {
head = null;
size = 0;
}
private class MyIterator implements Iterator {
public Node current = head;
@Override
public boolean hasNext() {
return current != null;
}
@Override
public Object next() {
Object o = current.data;
current = current.next;
return o;
}
}
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 (size() < 2) {
return;
}
Node newHeadNode = head;
Node curNode = newHeadNode.next;
newHeadNode.next = null;
Node nextNode;
do {
nextNode = curNode.next;
curNode.next = newHeadNode;
newHeadNode = curNode;
curNode = nextNode;
} while (curNode != null);
head = newHeadNode;
}
/**
* 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() {
if (size() < 2) {
return;
}
int i = (size()) / 2;
head = getNode(i);
size = size - i;
}
/**
* 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) {
throw new IndexOutOfBoundsException("index超出数组界限.");
}
if (i == 0) {
head = getNode(length);
}else if(i+length==size){
last= getNode(i-1);
last.next = null;
}else {
getNode(i - 1).next = getNode(i + length);
}
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) {
if (list == null || list.size() == 0) {
int[] arrElem = new int[size()];
Node node = head;
for (int i = 0; i < size(); i++) {
arrElem[i] = (int) node.data;
node = node.next;
}
return arrElem;
} else {
if (list.size() > size() || (int) list.get(list.size() - 1) + 1 > size()) {
throw new IndexOutOfBoundsException("超出数组界限。");
}
int[] arrElem = new int[list.size()];
int cur = 0;
Node node = head;
for (int i = 0; i < (int) list.get(list.size() - 1) + 1; i++) {
if (i == (int) list.get(cur)) {
arrElem[cur++] = (int) node.data;
}
node = node.next;
}
return arrElem;
}
}
/**
* 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) {
Node curNode = head;
int curIndex = 0;
for (int i = 0; i < list.size(); i++) {
int value = (int) list.get(i);
for (int j = curIndex; j < size(); j++) {
if (value == (int) curNode.data) {
remove(j);
break;
} else {
curNode = curNode.next;
}
}
curNode = head;
}
}
/**
* 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<Integer> set = new TreeSet<Integer>();
Node node = head;
for (int i = 0; i < size(); i++) {
set.add((Integer) node.data);
node = node.next;
}
clear();
for (Integer i : set) {
add(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) {
Node node = head;
int startIndex = -1;
int endIndex = size();
for (int i = 0; i < size(); i++) {
if (node == null) {
break;
}
int value = (int) node.data;
if (value < min) {
node = node.next;
continue;
}
if (value > max) {
endIndex = i - 1;
break;
}
if (startIndex == -1) {
startIndex = i;
}
node = node.next;
}
if (startIndex > -1) {
if (startIndex == 0 && endIndex == size()) {
clear();
return;
}
remove(startIndex, endIndex - startIndex);
}
}
/**
* 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 newList = new LinkedList();
Node aHead = head;
Node bHead = list.head;
for (int i = 0; i < list.size(); i++) {
int bValue = (int) bHead.data;
int aValue = 0;
do {
aValue = (int) aHead.data;
if (aHead == null || aValue > bValue) {
break;
}
if (aValue == bValue) {
newList.add(bValue);
aHead = aHead.next;
break;
} else {
aHead = aHead.next;
}
} while (aHead != null && (int) aHead.data <= bValue);
if (aHead == null) {
break;
}
bHead = bHead.next;
}
return newList;
}
public static void main(String[] args) {
LinkedList list = new LinkedList();
list.add(1);
list.add(2);
list.add(3);
list.add(4);
list.reverse();
for (int i = 0; i < list.size; i++) {
System.out.println(list.get(i));
}
// System.out.println(list.get(2));
// list.add(2, 100);
// System.out.println(list.get(2));
// list.addFirst(10);
// System.out.println(list.get(2));
// list.addLast(100);
// System.out.println(list.remove(1));
// System.out.println(list.removeFirst());
// System.out.println(list.removeLast());
}
}