归并排序与堆排序

#include <iostream>
using namespace std;

//  归并排序
void Merge(int a[],int b[],int i,int m,int n)
{
    int j,k;
    for(j = m+1,k=i;i<=m&&j<=n;k++)
    {
        if(a[i] < a[j]) 
            b[k] = a[i++];
        else 
            b[k] = a[j++];
    }

    if(i<=m) 
        for(int p=i;p<=m;p++,k++) b[k] = a[p];
    if(j<=n) 
        for(int p=j;p<=n;p++,k++) b[k] = a[p];
}

void copyArray(int a[],int b[],int s,int e)
{
    for(int i = s;i<=e;i++)
         b[i] = a[i];
}
void Merge_Sort(int a[],int b[],int s,int t)
{
    if(s == t) b[s] = a[s];
    else{
        int m = (s + t)/2;
        Merge_Sort(a,b,s,m);
        Merge_Sort(a,b,m+1,t);
        Merge(b,a,s,m,t);  
        copyArray(a,b,s,t); // 减少一个中间数组的空间开销
    }
}

void main()
{
    int a[10] = {5,4,3,2,-1,9,10,15,8,6};
    int b[10];
    Merge_Sort(a,b,0,9);
    for(int i=0;i<10;i++)
        cout << a[i] << endl;
}

#include <iostream>
#include <algorithm>
using namespace std;
// 大顶堆排序

void HeapAdjust(int a[],int p,int size)
{
    int lchild = 2*p;
    int rchild = 2*p+1;
    int max = p;
    if(p<=size/2)
    {
        if(a[max] < a[lchild] && lchild <=size) 
            max = lchild;
        if(a[max] < a[rchild] && rchild <=size) 
            max = rchild;
        if(max != p)
        {
            swap(a[max],a[p]);
            HeapAdjust(a,max,size);
        }
    }
}

void HeapSort(int a[],int s,int size)
{
    // 建堆
    for(int i=size/2;i>=s;i--)
        HeapAdjust(a,i,size);

    // 调整
    for(int i=size;i>=s;i--)
    {
        swap(a[s],a[i]);
        HeapAdjust(a,s,i-1);
    }
}

void main()
{
    int a[]= {5,1,4,3,2,-1,9,10,-15,19,20};

    HeapSort(a,1,10);
    for(int i=1;i<=10;i++)
        cout << a[i] << endl;
}

与书上的代码有点差别，个人理解的差别吧...