面试复习（C++）之堆排序

#include <iostream>

using namespace std;

void Maxheap(int *a,int i,int heapSize)//最大数调整
{
    int left=i*2+1;//i的左节点
    int right=i*2+2;
    int largest;//中间变量

    if(left<heapSize&&a[left]>a[i])
    {
        largest=left;
    }
    else
    {
        largest=i;
    }
    if(right<heapSize&&a[right]>a[largest])
    {
        largest=right;
    }
    if(largest!=i)
    {
        swap(a[i],a[largest]);
        Maxheap(a,largest,heapSize);
    }
}

void Maxheapbuild(int *a,int n)//最大数建造
{
    for(int i=n/2-1;i>=0;i--)
    {
        Maxheap(a,i,n-1);
    }
}

void Heapsort(int *a,int n)//堆排序
{
    Maxheapbuild(a,n);
    for(int i=n-1;i>0;i--)
    {
        swap(a[0],a[i]);
        Maxheap(a,0,i);
    }
}

int main()
{
    int n=5;
    int a[10];
    cout<<"Input Num"<<endl;
    for(int i=0;i<n;i++)
    {
        cin>>a[i];
    }
    Heapsort(a,n);
    for(int j=0;j<n;j++)
    {
        cout<<a[j]<<" ";
    }
    return 0;
}