算法导论第六章之——优先队列

优先队列类模版实现：

BuildMaxHeap.h头文件：

#include<iostream>
using namespace std;
#define Left(i) i*2+1
#define Right(i) i*2+2
#define Parent(i) (i-1)/2
void Max_Heapify(int a[],int length,int i)
{
	int left,right;
	left=Left(i);
	right=Right(i);
	int num=i;
	if(left<length&&a[left]>a[i])
	{
		num=left;
	}
	//此处逻辑判断出错，开始为else if，发现不能正确排序，改为else之后正确
	if(right<length&&a[right]>a[num])
	{
		num=right;
	}
	if(num!=i)
	{
		int temp;
		temp=a[i];
		a[i]=a[num];
		a[num]=temp;
		Max_Heapify(a,length,num);
	}
}
//此处添加利用循环方式代替递归Max_Heapify的函数，该函数可以替代Max_Heapify
//在某些情况下能取得更好 的效果
void Max_Heapify1(int a[],int length,int i)
{
	int left,right,num=i,largest=i;
	left=Left(i);
	right=Right(i);
	while(1)
	{
		if(a[left]>a[num]&&left<length)
		{
			largest=left;
		}
		//此处逻辑判断出错，开始为else if，发现不能正确排序，改为else之后正确
		if(a[right]>a[largest]&&right<length)
		{
			largest=right;
		}
		if(num!=largest)
		{
			int temp;
			temp=a[num];
			a[num]=a[largest];
			a[largest]=temp;
			num=largest;
			left=Left(num);
			right=Right(num);
		}
		else 
		{
			break;
		}
	}
	
}
void Build_Max_Heap(int a[],int length )
{
	int i;
	for(i=(length-1)/2;i>=0;i--)
	{
		Max_Heapify1(a,length,i);
	}
}

void Heap_Sort(int a[],int length)
{
	Build_Max_Heap(a,length);
	int i;
	int temp;
	for(i=length-1;i>=1;i--)
	{
		temp=a[i];
		a[i]=a[0];
		a[0]=temp;
		length-=1;
		Max_Heapify1(a,length,0);
	}
}

PriorQUeue.h

#include<iostream>
#include "BuileMaxHeap.h"
using namespace std;
#define MAX 100
template <typename type>class PriorQueue
{
private:
	int length;
	type a[MAX];
public:
PriorQueue ()
{
	int i;
	length=0;
	
	for(i=0;i<MAX;i++)
	{
		a[i]=0;
	}
}
	~PriorQueue()
	{
		
	}
	void BuildMaxHeapQueue();
	void Init(type b[],int len);
	type Maxnum();
	bool DeleteMax();
	void IncreaseKey(int i,type key);
	void Insert(type key);
	void Print();
	void Sort();
};
template<typename type>void PriorQueue<type>::Init(type b[],int len)
{
	int i;
	this->length=len;
	if(len<=0)
	{
		cout<<"Init failed !"<<endl;
	}
	for(i=0;i<len;i++)
	{
		a[i]=b[i];
	}
	BuildMaxHeapQueue();
}
template<typename type>void PriorQueue<type>::BuildMaxHeapQueue()
{
	Build_Max_Heap(a,length);
}
template<typename type>type  PriorQueue<type>::Maxnum()
{
	if(length<=0)
	{
		cout<<"the queue is empty!"<<endl;
		return -1;
	}
	return  a[0];
}
template<typename type>bool  PriorQueue<type>::DeleteMax()
{
	if(length<=0)
	{
		cout<<"the queue is empty!"<<endl;
		return 0;
	}
	a[0]=a[length-1];
	length-=1;
	Max_Heapify1(a,length,0);
	return 1;
}
template<typename type>void  PriorQueue<type>::IncreaseKey(int i,type key)
{
	int num=i;
	if(key<a[num])
	{
		cout<<"key is error!"<<endl;
		return ;
	}
	a[num]=key;
	while(num>0&&a[Parent(num)]<a[num])
	{
		type temp;
		temp=a[num];
		a[num]=a[Parent(num)];
		a[Parent(num)]=temp;
		num=Parent(num);
	}
}

template<typename type>void  PriorQueue<type>::Insert(type key)
{
	if(length>=MAX)
	{
		cout<<"the queue is full can't add more!"<<endl;
		return ;
	}
	length+=1;
	a[length-1]=key;
	IncreaseKey(length-1,key);
}
template<typename type>void  PriorQueue<type>::Print()
{
	int i;
	for(i=0;i<length;i++)
	{
		cout<<a[i]<<" ";
	}
	cout<<endl;
}
template<typename type>void  PriorQueue<type>::Sort()
{
	Heap_Sort(a,length);
}

 

main.cpp

#include"PriorQueue.h"
#include<iostream>
using namespace std;

int main()
{
	PriorQueue<int> node;
	int b[10]={4,1,3,2,16,9,10,14,8,7};
	node.Init(b,10);
	int i;
	node.Print();
	cout<<endl;
	cout<<node.Maxnum()<<endl;
	node.DeleteMax();
	node.Print();
	node.Insert(232);
	node.Sort();
	node.Print();
	return 0;
}