線性表

         線性表是其組成元素具有線性關係的一種線性結構，對線性表的基本操作主要有獲得元素值、設置元素值、插入、刪除、查找、替換和排序等，插入和刪除操作可以在線性表的 任意位置進行。

       線性表有順序表和鏈表兩種。順序表存儲方式是在內存開闢一組連續的空間存放數據元素，元素的內存物理存儲次序和它們在線性表中的邏輯次序相同。鏈表的存儲方式是用若干地址分散的存儲單元存儲數據元素，邏輯上相鄰的兩個元素在內存中的物理位置不一定相同。所以，在鏈表中每個節點都有下一個節點的信息。

      下面是兩種不同的實現方式：

       定義一個公共的線性表接口，順序表和鏈表都實現此接口，

      public interface LList<T> {
     boolean isEmpty();
     int length();
     T get(int i);
     void set(int i,T x);
     void insert(int i,T x);
     void append(T x);
     T remove(int i);
     void removeAll();
   }

順序表：

public class SeqList<T> implements LList<T> {
    private Object[] element;
private int len;
    public SeqList(int size){
    this.element = new Object[size];
    this.len = 0;
    }
    public SeqList(){this(64);}
@Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return this.len == 0;
}


@Override
public int length() {
// TODO Auto-generated method stub
return this.len;
}


@Override
public T get(int i) {
// TODO Auto-generated method stub
if(i >= 0 && i < len){
return (T)this.element[i];
}
return null;
}


@Override
public void set(int i, T x) {
// TODO Auto-generated method stub
if(x == null){
return;
}
if(i >= 0 && i < len){
this.element[i] = x;
}else
throw new IndexOutOfBoundsException(i + "");
}


@Override
public void insert(int i, T x) {
// TODO Auto-generated method stub
if(x == null){
return;
}
if(this.len == element.length){
Object[] temp = this.element;
Object[] element = new Object[temp.length * 2];
for(int j = 0;j < temp.length;j ++){
this.element[j] = temp[j];
}
}
if(i < 0)
i = 0;
if(i > this.len)
i = this.len;
for(int j = this.len;j > i;j --){
this.element[j] = this.element[j-1];
}
this.element[i] = x;
this.len ++;
}


@Override
public void append(T x) {
// TODO Auto-generated method stub
   insert(this.len,x);
}


@Override
public T remove(int i) {
// TODO Auto-generated method stub
if(i >= 0 && i < len){
T temp = (T)element[i];
for(int j = i;j < len - 1;j ++){
element[j] = element[j+1];
}
element[this.len-1] = null;
this.len --;
return temp;
}
return null;
}


@Override
public void removeAll() {
// TODO Auto-generated method stub
this.len = 0;
}


public String toString(){
    String str="(";
    if(this.len > 0)
    str += this.element[0].toString();
    for(int i = 1;i < this.len;i ++)
    str += this.element[i].toString();
    return str += ")";
    }
    //比較兩個順序表是否相等
    public boolean equals(Object obj){
    if(obj == null)
    return false;
    if(obj instanceof SeqList){
    SeqList<T> list = (SeqList<T>)obj;
    if(this.length() == list.length()){
    for(int i = 0;i <this.length();i ++){
    if(!(this.get(i)).equals(list.get(i)))
    return false;
    }
    return true;
    }
    }
    return false;
    }
}

鏈表：

public class LinkedList<T> implements LList<T> {
    public Node<T> head;
public LinkedList(){
    this.head = new Node<T>();
    }
public LinkedList(T[] element){
this();
Node<T> rear = this.head;
for(int i = 0;i < element.length;i ++){
rear.next = new Node<T>(element[i],null);
rear = rear.next;
}
}
@Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return this.head.next == null;
}


@Override
public int length() {
// TODO Auto-generated method stub
int i = 0;
Node<T> p = this.head.next;
while(p != null){
p = p.next;
i++;
}
return i;
}


@Override
public T get(int i) {
// TODO Auto-generated method stub
if(i >= 0){
Node<T> p = this.head.next;
             for(int j = 0;p != null && j <i;j ++){
            p = p.next;
             }
             if(p != null)
            return p.date;
}
return null;
}


@Override
public void set(int i, T x) {
// TODO Auto-generated method stub
if(x == null)
return;
if(i >= 0){
Node<T> p = this.head.next;
for(int j = 0;p != null && j < i;j ++){
p = p.next;
}
if(p != null)
p.date = x;
}else
throw new IndexOutOfBoundsException(i + "");
}


@Override
public void insert(int i, T x) {
// TODO Auto-generated method stub
if(x == null)
return;
Node<T> p = this.head;
for(int j = 0;p.next != null && j < i;j ++)
p = p.next;
   p.next = new Node<T>(x,p.next);
}


@Override
public void append(T x) {
// TODO Auto-generated method stub
insert(Integer.MAX_VALUE,x);
}


@Override
public T remove(int i) {
// TODO Auto-generated method stub
if(i >= 0){
Node<T> p = this.head;
for(int j = 0;p.next != null && j < i;j ++)
p = p.next;
if(p.next != null){
T old = p.next.date;
p.next = p.next.next;
return old;
}
}
return null;
}


@Override
public void removeAll() {
// TODO Auto-generated method stub
this.head.next = null;
}


public boolean equals(Object obj){
if(obj == this)
return true;
if(!(obj instanceof LinkedList)) 
return false;
Node<T> p = this.head.next;
Node<T> q = ((LinkedList<T>)obj).head.next;
while(p != null && q != null && p.date.equals(q.date)){
p = p.next;
q = q.next;
}
return p == null && q == null;
}

public String toString(){
String str = "(";
Node<T> p = this.head.next;
while(p != null){
str += p.date.toString();
if(p.next != null)
str += ",";
p = p.next;
}
return str + ")";
}
}
class Node<T>{
public T date;
public Node<T> next;
public Node(T date,Node<T> next){
this.date = date;
this.next = next;
}
public Node(){this(null,null);}
}