归并排序

/*归并排序是建立在归并操作上的一种有效的排序算法。该算法是采用分治法（Divide and Conquer）的一个非常典型的应用。归并排序是一种稳定的排序方法。将已有序的子序列合并，得到完全有序的序列；即先使每个子序列有序，再使子序列段间有序。若将两个有序表合并成一个有序表，称为2-路归并。*/#include<iostream>#include<stdio.h>using namespace std;///将有二个有序数列a[first...mid]和a[mid...last]合并。void mergearray(int a[], int first, int mid, int last, int temp[]){    int i = first, j = mid + 1;    int m = mid,   n = last;    int k = 0;    while (i <= m && j <= n)    {        if (a[i] <= a[j])            temp[k++] = a[i++];        else            temp[k++] = a[j++];    }    while (i <= m)        temp[k++] = a[i++];    while (j <= n)        temp[k++] = a[j++];    for (i = 0; i < k; i++)        a[first + i] = temp[i];}///递归地完成归并排序void mergesort(int a[], int first, int last, int temp[]){    if (first < last)    {        int mid = (first + last) / 2;        mergesort(a, first, mid, temp);    ///左边有序        mergesort(a, mid + 1, last, temp); ///右边有序        mergearray(a, first, mid, last, temp); ///再将二个有序数列合并    }}int main(){    int a[10],temp[10];    for(int i = 0; i < 10; i ++)        scanf("%d",&a[i]);    mergesort(a,0,9,temp);    for(int i = 0; i < 10; i ++)        cout << temp[i] << " ";    cout << endl;    return 0;}