package 隊列和堆棧;
import java.util.*;
public class LinkedListQueueTest {
//字段
private LinkedList list;
//無參數構造
public LinkedListQueueTest()
{
list=new LinkedList();
}
//隊列元素的個數
public int size()
{
return list.size();
}
//進入隊列
public void enqueue(Object obj)
{
list.addLast(obj);
}
//對頭出來
public Object dequeue()
{
return list.removeFirst();
}
//瀏覽對頭元素
public Object front()
{
//return list.getFirst();
return list.peekFirst();
}
//判斷隊列是否為空
public boolean isEmpty()
{
return list.isEmpty();
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
LinkedListQueueTest llq=new LinkedListQueueTest();
System.out.println(llq.isEmpty());
llq.enqueue("147");
llq.enqueue("258");
llq.enqueue("369");
System.out.println(llq.size());
System.out.println("移除隊列頭元素："+llq.dequeue());
System.out.println(llq.size());
llq.enqueue("abc");
llq.enqueue("def");
System.out.println(llq.size());
System.out.println("查看隊列的頭元素："+llq.front());
System.out.println(llq.size());
System.out.println(llq.isEmpty());
}
}
通過數組實現
package 隊列和堆棧;
import java.util.NoSuchElementException;
//通過數組來實現隊列
public class ArrayQueue {
//字段
public static Object[] data;
//隊列的元素個數
protected int size ;
//隊列頭
protected int head;
//隊列尾
public static int tail;
/**
*
*/
//無參數構造函數
public ArrayQueue() {
final int INITIAL_LENGTH=3;
data=new Object[INITIAL_LENGTH];
size=0;
head=0;
tail=-1;
}
//隊列元素個數方法
public int size()
{
return size;
}
public boolean isEmpty()
{
return size==0;
}
//得到隊列頭元素
public Object front()
{
if(size==0)
throw new NoSuchElementException();
return data[head];
}
//進入隊列enqueue()方法
public void enqueue(Object obj)
{
//此時隊列已經滿
if(size==data.length){
Object[] oldData=data;
data=new Object[data.length*2];
//if(head==0)
System.arraycopy(oldData, head, data, 0, oldData.length-head);
if(head>0)
System.arraycopy(oldData, 0, data, head+1, tail+1);
head=0;
tail=oldData.length-1;
}
tail=(tail+1)%data.length;
size++;
data[tail]=obj;
}
//隊列的元素出隊
public Object dequeue()
{
if(size==0)
throw new NoSuchElementException();
Object ele=data[head];
//循環隊列
head=(head+1)%data.length;
size--;
return ele;
}
@Override
public String toString() {
// TODO Auto-generated method stub
return super.toString();
}
}
通過向量實現：
//通過向量實現棧
package 隊列和堆棧;
import java.util.*;
public class VectorStackTest {
//字段
Vector v;
//構造函數
public VectorStackTest()
{
v=new Vector();
}
//元素的個數
public int size()
{
return v.size();
}
//是否為空
public boolean isEmpty()
{
return size()==0;
}
//進棧
public Object Push(Object obj)
{
v.addElement(obj);
return obj;
}
//出棧方法
public Object Pop()
{
int len=size();
Object obj=Peek();
v.removeElementAt(len-1);
return obj;
}
//查看棧頂元素
public Object Peek()
{
int len = size();
if (len == 0)
throw new EmptyStackException();
return v.elementAt(len - 1);
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
VectorStackTest vst=new VectorStackTest();
System.out.println("大小："+vst.size());
vst.Push("123");
vst.Push("456");
vst.Push("789");
vst.Push("abc");
System.out.println("大小："+vst.size());
System.out.println("棧頂："+vst.Peek());
System.out.println("出棧："+vst.Pop());
vst.Push("def");
vst.Push("147");
System.out.println("大小："+vst.size());
System.out.println("棧頂："+vst.Peek());
System.out.println("出棧："+vst.Pop());
System.out.println(vst.Peek());
vst.Push("def");
vst.Push("147");
System.out.println(vst.Pop());
System.out.println(vst.Pop());
System.out.println(vst.Peek());
System.out.println(vst.Pop());
System.out.println(vst.Pop());
vst.Push("1aadf");
vst.Push("2dafad");
vst.Push("123789");
System.out.println(vst.Pop());
System.out.println(vst.Peek());
System.out.println(vst.Pop());
System.out.println(vst.Peek());
System.out.println("------------------end------------");
VectorStackTest llst=new VectorStackTest();
llst.Push("123");
llst.Push("456");
System.out.println("棧頂："+llst.Peek());
System.out.println("出棧："+llst.Pop());
System.out.println(llst.Peek());
llst.Push("789");
llst.Push("abc");
System.out.println("棧頂："+llst.Peek());
System.out.println("出棧："+llst.Pop());
System.out.println(llst.size());
System.out.println("棧頂："+llst.Peek());
}
}
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