23-5-11-归并排序--归并排序模板

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cmath>
using namespace std;
void merge(int* a, int low, int mid, int hight)  //合并函数
{
    int* b = new int[hight - low + 1];  //用 new 申请一个辅助函数
    int i = low, j = mid + 1, k = 0;    // k为 b 数组的小标
    while (i <= mid && j <= hight)  
    {
        if (a[i] <= a[j])
        {
            b[k++] = a[i++];  //按从小到大存放在 b 数组里面
        }
        else
        {
            b[k++] = a[j++];
        }
    }
    while (i <= mid)  // j 序列结束，将剩余的 i 序列补充在 b 数组中 
    {
        b[k++] = a[i++];
    }
    while (j <= hight)// i 序列结束，将剩余的 j 序列补充在 b 数组中 
    {
        b[k++] = a[j++];
    }
    k = 0;  //从小标为 0 开始传送
    for (int i = low; i <= hight; i++)  //将 b 数组的值传递给数组 a
    {
        a[i] = b[k++];
    }
    delete[]b;     // 辅助数组用完后，将其的空间进行释放（销毁）
}
void mergesort(int* a, int low, int hight) //归并排序
{
    if (low < hight)
    {
        int mid = (low + hight) / 2;
        mergesort(a, low, mid);          //对 a[low,mid]进行排序
        mergesort(a, mid + 1, hight);    //对 a[mid+1,hight]进行排序
        merge(a, low, mid, hight);       //进行合并操作
    }
}
int main()
{
    int n, a[100];
    cout << "请输入数列中的元素个数 n 为：" << endl;
    cin >> n;
    cout << "请依次输入数列中的元素：" << endl;
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
    mergesort(a, 0, n-1);
    cout << "归并排序结果" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << a[i] << " ";
    }
    cout << endl;
    return 0;
}