隊列(queue)的鏈表與數組表示

文章目錄

• 根據方法1實現的隊列
• 根據方法2實現的隊列

隊列實際上是一個受限的線性表.所以可以利用單鏈表一部分功能來實現.

單鏈表的定義見:http://blog.csdn.net/weiwenhp/article/details/8634469

 

1.隊列的鏈表表示

#include
"LinkList.h"

 

template<class T>

class LinkQueue

{

private:

LinkList<T> m_pList;

public:

void EnQue(T val){m_pList.Add(val);}  //入棧

T GetRear(){return m_pList.GetTailVal();} //返回棧尾元素值

 

T DeQue(){ //出棧

T val = m_pList.GetHeadVal();

m_pList.RemoveAt(0);

return val;

}

T GetFront(){return m_pList.GetHeadVal();} //返回棧頭部元素值

 

int Size(){
return m_pList.Size();}

void Clear() { m_pList.Clear(); }

};

 

2.隊列的數組表示

一般用數組表示隊列時,為了充分利用空間,採用所謂的迴圈隊列表示.數組邏輯上變得是首尾相連了.

假設列隊頭部指標為front,尾指標為rear.當數組全部容量用來裝隊列元素時,由於數組滿的時候和空的時候都是front==rear,為了區分隊列是滿還是空有兩種方法.

1.使用一個額外的變數size來表示元素個數,但元素個數等於數組容量maxSize時表示滿了

2.不使用額外變數,而是讓元素總個數比數組容量小1,這樣當隊列頭指標等於尾指標時表示為空白,兩者相減為1時表示滿了.

 

根據方法1實現的隊列

 

#include <iostream>

using namespace std;

 

const static
int QUE_SIZE = 100;

template<class T>

class QueArray

{

private:

T* m_pArray; //表示隊列的數組

int m_nSize; //當前元素個數

int m_nMaxSize; //數組可容納最大元素數量

int front; //隊頭部

int rear; //隊列尾部

 

public:

QueArray(int nMaxSize = QUE_SIZE){

m_nMaxSize = nMaxSize;

m_pArray = new T[m_nMaxSize];

m_nSize = front = rear = 0;

}

~QueArray(void){
delete []m_pArray;}

bool IsFull(){
return m_nSize > m_nMaxSize
;}

bool IsEmpty(){
return m_nSize ==0;}

int Size(){
return m_nSize;}

void Clear() { m_nSize = front = rear = 0; }

 

bool EnQue(T val){  //隊列尾部添加元素

if(IsFull()){

cout<<"queue is full."<<endl;

return
false;

}

m_pArray[rear] = val;

rear = (rear + 1) % m_nMaxSize;

m_nSize++;

}

T GetRear() { //返回隊列尾部元素

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

return m_pArray[rear -1];

}

 

T DeQue(){ //返回隊列頭部元素並刪除

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

T val = m_pArray[front];

front = (front + 1) % m_nMaxSize;

m_nSize --;

return val;

}

T GetFront(){ //返回頭部元素

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

return m_pArray[front];

}

};

 

 

根據方法2實現的隊列

#include <iostream>

using namespace std;

 

const static
int QUE_SIZE = 100;

template<class T>

class QueArray

{

private:

T* m_pArray; //隊列數組

int m_nMaxSize; //可容納最大元素個數

int front; //頭部元素

int rear; //尾部元素

public:

QueArray(int nMaxSize = QUE_SIZE){

m_nMaxSize = nMaxSize;

m_pArray = new T[m_nMaxSize + 1]; //數組元素比最大容量大1

front = rear = 0;

}

~QueArray(void){
delete []m_pArray;}

 

bool IsFull(){
return (rear+1)%m_nMaxSize == front;}

bool IsEmpty(){
return front == rear;}

int Size(){
return m_nSize;}

void Clear() { m_nSize = front = rear = 0; }

 

bool EnQue(T val){

if(IsFull()){

cout<<"queue is full."<<endl;

return
false;

}

m_pArray[rear] = val;

rear = (rear + 1) % m_nMaxSize;

}

T GetRear() {

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

return m_pArray[rear -1];

}

 

T DeQue(){

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

T val = m_pArray[front];

front = (front + 1) % m_nMaxSize;

return val;

}

T GetFront(){

if(IsEmpty()){

cout<<"queue is empty"<<endl;

return NULL;

}

return m_pArray[front];

}

};