c++实现的最小堆类

最新推荐文章于 2024-08-19 20:19:26 发布

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#编程 #算法 #c++ #heap

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本文介绍了一种使用C++实现的最小堆数据结构，并提供了完整的类定义和成员函数实现，包括初始化、插入、删除最小元素等操作。

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今天复习最小堆，用c++写了一个最小堆的类，贴出来分享给大家。

#include <iostream>

using namespace std;

template <class T>
class MinHeap{
    public:
        void HeapInitialize(T a[],int size,int ArraySize);
       MinHeap<T> &Insert(const T &x);
       MinHeap<T> &DeleteMin(T &x);
       void Print();
       bool IsEmpty();
       int Size();
   private:
        T *Heap;
        int CurrentSize;
        int MaxSize;
};

template <class T>
void MinHeap<T>::HeapInitialize(T a[],int size,int ArraySize)
{
    Heap = (T*)malloc(ArraySize*sizeof(T));

    for(int m=0;m<size;m++)
        Heap[m] = a[m];

    CurrentSize = size;
    MaxSize = ArraySize;
    for(int i = (CurrentSize-1)/2;i>=0;i--)
    {
        T y = Heap[i];
        int c = 2*i;
        while(c<CurrentSize)
        {
            if(c<CurrentSize-1&&Heap[c]>Heap[c+1])
                c++;
            if(y<=Heap[c])
                break;
            else
            {
                Heap[c/2] = Heap[c];
                c*=2;
             }
        }
        Heap[c/2] = y;
    }
}
template <class T>
MinHeap<T> &MinHeap<T>::Insert(const T &x)
{
    if(CurrentSize==MaxSize)
        exit(1);
    int i = CurrentSize++;
    while(i!=0 && x<Heap[i/2])
    {
        Heap[i] = Heap[i/2];
        i /= 2;
    }
    Heap[i] = x;
    return *this;
}
template <class T>
MinHeap<T> &MinHeap<T>::DeleteMin(T &x)
{
    if(CurrentSize==0)
        exit(1);
    x = Heap[0];
    T y = Heap[--CurrentSize];
    int i = 0,ci = 1;
    while(ci<CurrentSize)
    {
        if(ci<CurrentSize-1 && Heap[ci]>Heap[ci+1])
            ci++;
        if(Heap[ci]<y)
        {
            Heap[i] = Heap[ci];
            i = ci;
            ci *= 2;
         }
         else
            break;
    }
    Heap[i] = y;
    return *this;
}

template <class T>
void MinHeap<T>::Print()
{
    for(int i=0;i<CurrentSize;i++)
        cout<<Heap[i]<<" ";
    cout<<endl;
}

template <class T>
bool MinHeap<T>::IsEmpty()
{
    if(CurrentSize>0)
        return false;
    else
        return true;
}

template <class T>
int MinHeap<T>::Size()
{
    return CurrentSize;
}

void main()
{
    int arr[] = {2,1,5,3,2,4,6,34,3};
    MinHeap<int> *mh = new MinHeap<int>();
     mh->HeapInitialize(arr,9,20);
    cout<<"Original heap:";
     mh->Print();
    int x;
    mh->Insert(7);
    mh->Insert(11);
    mh->Insert(23);
    mh->Insert(10);
    mh->Insert(11);
    cout<<"After inserting:";
    mh->Print();

    cout<<"Extract from heap:";
     while(!mh->IsEmpty())
    {
        mh->DeleteMin(x);
        cout<<x<<" ";
    }
    cout<<endl;
}