C++ 实现优先队列的简单实例

C++ 实现优先队列的简单实例

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;
}

以上就是数据结构优先队列的实例，如有疑问请留言或者到本站社区交流讨论，感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！