C++最大Heap

最新推荐文章于 2024-08-10 16:41:29 发布

原创最新推荐文章于 2024-08-10 16:41:29 发布 · 133 阅读

0 ·

CC 4.0 BY-SA版权

本文介绍了一个通用的最大堆实现，并展示了如何使用该实现进行插入、删除最大元素等基本操作。通过具体的代码示例，读者可以了解到最大堆的内部工作原理及其在实际应用中的使用方法。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

#include <iostream>
using namespace std;
template <class T>
class MaxHeap{
	T* heap;
	int curSize;
	int maxSize;
	public:
		MaxHeap(int maxSize=10)
		{
		   maxSize=maxSize;
		   curSize=0;
		   heap=new T[maxSize+1];
		}
		~MaxHeap(){
			delete heap;
		}
		//get the curSize of this heap
		int Get_Size() const 
		{
			return curSize;
		}
		//get the max value,at the first position of the array
		T Get_Max()
		{
			if (curSize==0)
			{
				return NULL;
			}
			else
			{
				return heap[1];
			}
		}
		//insert a new element into the heap
		void insert(const T& x)
		{
			if (curSize==maxSize)
			{
				cout<<"the heap is full"<<endl;
				return;
			}
			int i=++curSize;
			while (i>=1&&x>heap[i/2])
			{
				heap[i]=heap[i/2];
				i/=2;
			}
			heap[i]=x;
			cout<<"insert successfully: "<<x<<endl;

		}
		//delete the element with the max value,and save it into the parameter
		void DeleteMax(T& x)
		{
			if (curSize==0)
			{
				cout<<"the heap is empty,can not delete"<<endl;
				x=-9999;
				return;
			}
            x=heap[1];
			heap[0]=heap[curSize--];
			int i=1;
			int ci=2;
			while (ci<=curSize)
			{
				//ci是较大的孩子的位置
				if (heap[ci]<heap[ci+1]&&ci<=curSize)
				{
					ci++;
				}
				if (heap[0]>heap[ci])
				{
					break;
				}
				else
				{
					heap[i]=heap[ci];//move up the ci
					i=ci;
					ci*=2;
				}


			}
			heap[i]=heap[0];

		}
		void Init_heap(T a[],int size,int maxsize)
		{
			delete[] heap;
			heap=new T[maxsize+1];
			this->curSize=size;
			this->maxSize=maxsize;
			for (int j=1;j<=size+1;j++)
			{
				
				heap[j]=a[j-1];
			}
			for (int i=size/2;i>=1;i--)
			{
				T y=heap[i];//the root element of the current subtree

				int c=2*i;//begin to find the position to place y	
                
				while (c<=size)
				{
				
					if (c<curSize&&heap[c+1]>heap[c])
					{
						c++;
					}
					if (y>=heap[c])
					{
						break;
					}
					heap[c/2]=heap[c];
					c*=2;
				}
				heap[c/2]=y;
			}
			
		}

};
int main()  
{  
    MaxHeap<int> hp;  
    int a[11]={-111,5,2,12,3,55,21,7,9,11,9};  
	
    cout<<"用数组a来初始化堆："<<endl;  
    for(int i=1;i<11;i++)  
        cout<<a[i]<<"  ";  
    cout<<endl;  
	
    hp.Init_heap(a,10,15);  
	
    int max;  
    cout<<"目前堆中最大值为："<<hp.Get_Max()<<endl;  
	
    hp.DeleteMax(max);  
    cout<<"删除的堆中最大的元素为："<<max<<endl;  
    cout<<"删除后，现在堆中最大的元素为："<<hp.Get_Max()<<endl;  
	
    cout<<"现在堆的大小为："<<hp.Get_Size()<<endl;  
	
    cout<<"向堆中插入新元素"<<endl;  
	
    hp.insert(22);  
    hp.insert(45);  
    hp.insert(214);  
    hp.insert(16);  
    hp.insert(21);  
    hp.insert(121);  
    hp.insert(111);  
	
    cout<<"插入后现在堆的大小为："<<hp.Get_Size()<<endl;  
	
    cout<<"现在由大到小输出堆中元素"<<endl;  
	
    do  
    {  
        hp.DeleteMax(max);  
        if(max== -9999)  
            break;  
        cout<<max<<"  ";  
    }while(1);  
	
    cout<<endl;  
	
    return 0;  
}