数据结构-堆排序

#include <iostream>

using namespace std;

void Sort(int* a,int num,int n){
    int c = 2 * num + 1;

    while(c+1 < n){
        if(a[c+1] > a[c]){
            c++;
        }
        if(a[c] > a[num]){
            int tmp = a[c];
            a[c] = a[num];
            a[num] = tmp;
            num = c;
            c = 2 * num + 1;
        }
        else{
            break;
        }
    }
    if(c+1 == n){
        if(a[c]>a[num]){
            int tmp = a[c];
            a[c] = a[num];
            a[num] = tmp;
        }
    }
}

void CreateHeap(int* a,int n){
    int t = (n-1) / 2;       //最后一个非叶子点
    for(int i=t;i>=0;i--){
        Sort(a,i,n);
    }
}

void HeapSort(int* a,int n){
    for(int i=n-1;i>=0;i--){
        int tmp = a[i];
        a[i] = a[0];
        a[0] = tmp;
        Sort(a,0,i);    //因为把0和最后的元素交换，所以每次都只需要从0开始构建heap
    }

}

int main()
{
    int a[] = {5,2,8,7,4,1,6,9,3,10};
    int n = 10;

    CreateHeap(a,n);
    HeapSort(a,n);

    for(int i=0;i<n;i++){
        cout << a[i] << " ";
    }

    return 0;
}