c++归并排序算法

归并排序

---

代码

#include "stdafx.h"
#include "iostream"
using namespace std;

void merge(int*,int,int);
void mergeSort(int *, int, int, int);

int _tmain(int argc, _TCHAR* argv[])
{
    int count;
    int* a;
    cout << "请输入你将要输入排序数字的个数:";
    cin >> count;

    a = new int[count];
    cout << "请输入你将要排序的数字:";

    for (int i = 0; i < count; i++)
    {
        cin >> a[i];
    }
    merge(a, 0, count-1);

    for (int i = 0; i < count; i++)
    {
        cout<< a[i] <<' ';
    }
    system("pause");
    return 0;
}

void merge(int* sort,int first, int last)
{
    int mid = 0;
    if (first + 1 < last)
    {
        mid = (first + last) / 2; 
        merge( sort,  first, mid);
        merge(sort,  mid + 1, last);
        mergeSort(sort, first, last, mid);
    }
    else 
    {
        if (sort[first] > sort[last])
        {
            int temp = sort[first];
            sort[first] = sort[last];
            sort[last] = temp;
        }
    }

}

void mergeSort(int* sort, int first, int last, int mid)
{
    int i, j, m ,l, k;
    i = first;
    j = mid + 1;
    l = last;
    k = 0;
    m = mid;
    int* temp = new int[last + 1 - first];
    while (i <= m && j <= l)
    {
        if (sort[i] < sort[j])
        {
            temp[k++] = sort[i++];
        }
        else
        {
            temp[k++] = sort[j++];
        }
    }
    while (i <= m)
    {
        temp[k++] = sort[i++];
    }
    while (j <= l)
    {
        temp[k++] = sort[j++];
    }
    for (i = 0; i < k; i++)
    {
        sort[first + i] = temp[i];
    }
}

总结

通过代码方便以后学习，如果有什么错误希望各路大神指出，不胜感激。