C++实现优先队列

/[b]***********[/b]优先队列的(单向)链式实现形式[b]*************[/b]/

节点类

template

class QueueNode

{

public:

Type data;//数据

int priority;//优先级

QueueNode *next;

QueueNode() :data(Type()), priority(0), next(nullptr){}

QueueNode(Type d, int p, QueueNode *n=nullptr) :data(d), priority(p), next(n){}

};

//优先队列类

template

class Priority_Queue

{

private:

QueueNode *front;//队头指针

QueueNode *rear;//队尾指针

int length;//队列长度

public:

Priority_Queue();

~Priority_Queue();

bool isEmpty(){ return this->length == 0; }

int size() const { return this->length; }

bool Push(const Type &d, int p);

bool Pop();

Type GetHead();

void ShowQueue() const;

};

//构造函数

template

Priority_Queue::Priority_Queue() :length(0)

{

cout << “构造函数，创建一个节点” << endl;

this->front = this->rear = new QueueNode();

}

//析构函数

template

Priority_Queue::~Priority_Queue()

{

cout << “析构函数” << endl;

QueueNode *dnode = this->front;

QueueNode *tmp = this->front;

while (tmp != nullptr)

{

tmp = tmp->next;

delete dnode;

dnode = tmp;

}

}

//添加节点

template

bool Priority_Queue::Push(const Type &d, int p)

{

QueueNode *add = new QueueNode(d, p, nullptr);//将要插入的节点

if (add == nullptr)

return false;

//要根据优先级构造队列，数字越小优先级越高应该， 数字最小的应该放在最前面

if (this->front == this->rear)

{

cout << “该队列为空，直接将节点插入即可” << endl;

this->rear->next = add;

this->rear = add;

this->length++;

return true;

}

QueueNode *move = this->front->next;//移动指针找到第一个比塔优先级小的节点

while (move->priority < add->priority && move != nullptr)

move = move->next;

if (move == nullptr)//说明队列中的优先级都比add大，直接将节点插在队尾即可

{

this->rear->next = add;

this->rear = add;

this->length++;

return true;

}

QueueNode *tmp = this->front;

while (tmp->next != move)

tmp = tmp->next;

add->next = move;

tmp->next = add;

this->length++;

return true;

}

template

bool Priority_Queue::Pop()

{

if (this->length == 0)

{

cout << “队列为空，无法输出” << endl;

return false;

}

QueueNode *dnode = this->front->next;

this->front->next = dnode->next;

if (this->length == 1)

this->rear = this->front;

delete dnode;

this->length–;

return true;

}

template

Type Priority_Queue::GetHead()

{

if (this->length == 0)

{

cout << “队列为空，无法获得第一个元素的值” << endl;

return 0;

}

return this->front->next->data;

}

template

void Priority_Queue::ShowQueue() const

{

if (this->length == 0)

{

cout << “队列为空，无法输出” << endl;

return;

}

QueueNode *move = this->front->next;

int i = 0;

while (move != nullptr)

{

cout << “第” << i + 1 << “个元素输出: ” << endl

<< “data:” << move->data << endl

<< “priority:” << move->priority << endl;

move = move->next;

i++;

}

}

//测试程序

int main()

{

Priority_Queue queue;

for (int i = 0, j = 10; i < 10, j>0; i++, j–)

queue.Push(i + 1, j);

queue.Push(100, 4);

//queue.ShowQueue();

for (int i = 0; i < 5; i++)

queue.Pop();

queue.ShowQueue();

return 0;

}

/[b]***********[/b]优先队列的(双向)链式实现形式[b]*************[/b]/

//队列节点类

template

class QueueNode

{

public:

Type data;//数据域

int priority;//优先级

QueueNode *next;//后继指针

QueueNode *prev;//前向指针

QueueNode() :data(Type()), priority(0), next(nullptr), prev(nullptr){}

QueueNode(Type d, int pri, QueueNode *n = nullptr, QueueNode *p = nullptr) :data(d), priority(pri), next(n), prev(p){}

};

//优先队列类

template

class Priority_Queue

{

private:

QueueNode *front;//头指针

QueueNode *rear;//尾指针

int length;//队列长度

public:

Priority_Queue();

~Priority_Queue();

bool isEmpty(){ return this->length == 0; }

int size() const { return this->length; }

bool Push(const Type &d, int p);

bool Pop();

Type GetHead();

void ShowQueue() const;

};

//构造函数

template

Priority_Queue::Priority_Queue() :length(0)

{

cout << “构造函数,创建一个头节点” << endl;

this->front = this->rear = new QueueNode();

}

//析构函数

template

Priority_Queue::~Priority_Queue()

{

cout << “析构函数” << endl;

/*QueueNode *dnode = this->front;

QueueNode move = this->front;/

}

//添加节点

template

bool Priority_Queue::Push(const Type &d, int p)

{

QueueNode *add = new QueueNode(d, p, nullptr, nullptr);//将要插入的节点

if (add == nullptr)

return false;

if (this->length == 0)

{

//cout << “链表为空，直接插入即可” << endl;

this->front->next = add;

add->prev = this->front;

this->rear = add;

this->length++;

return true;

}

//加入链表不为空，排序添加节点

QueueNode *move = this->front->next;

while (move->priority < add->priority && move != nullptr)

move = move->next;

if (move == nullptr)

{

//说明队列中所有元素的优先级都比add大，直接插在队后即可

this->rear->next = add;

add->prev = this->rear;

this->rear = add;

this->length++;

return true;

}

move->prev->next = add;

add->prev = move->prev;

add->next = move;

move->prev = add;

this->length++;

return true;

}

//删除节点

template

bool Priority_Queue::Pop()

{

if (this->length == 0)

{

cout << “队列为空，无法删除” << endl;

return false;

}

if (this->length == 1)

{

delete this->front->next;

this->front->next = nullptr;

this->rear = nullptr;

this->length–;

return true;

}

QueueNode *dnode = this->front->next;

this->front->next = dnode->next;

dnode->next->prev = this->front;

delete dnode;

this->length–;

return true;

}

//获取第一个元素的值

templat
4000
e

Type Priority_Queue::GetHead()

{

if (this->length == 0)

{

cout << “队列为空，无法查看第一个元素的值” << endl;

return 0;//返回0是没有元素

}

return this->front->next->data;

}

//输出队列

template

void Priority_Queue::ShowQueue() const

{

if (this->length == 0)

{

cout << “队列为空，无法删除” << endl;

return;

}

QueueNode *move = this->front->next;

int i = 0;

while (move != nullptr)

{

cout << “第” << i + 1 << “个元素输出: ” << endl

<< “data:” << move->data << endl

<< “priority:” << move->priority << endl;

move = move->next;

i++;

cout << endl;

}

}

//测试程序

int main()

{

Priority_Queue queue;

for (int i = 0, j = 10; i<10, j>0; i++, j–)

queue.Push(i, j);

queue.Push(1, 2);

//queue.Pop();

queue.ShowQueue();

return 0;

}