程序代码：

#include<stdio.h>
#include<stdlib.h>
#define MAX 255

int R[MAX]={0};
void Merge(int low,int m,int high);
void Merge_SortDC(int low,int high);

int main()
{
    int i=0;
    int n=0;

    puts("Please input total element number of the sequence:");

    scanf("%d",&n);

    if (n<1||n>MAX)
    {
        printf("n must more than 0 and less than %d.\n",MAX);
        exit(0);
    }

    puts("Please input the elements one by one:");

    for (i=1;i<=n;++i)
        scanf("%d",&R[i]);

    puts("The sequence you input is:");

    for (i=1;i<=n;++i)
        printf("%-4d",R[i]);

    Merge_SortDC(1,n);

    puts("\nThe sequence after merge_sortDC is:");

    for (i=1;i<=n;++i)
        printf("%-4d",R[i]);

    puts("");

    return 0;
}

void Merge(int low,int m,int high)
{
    /*将两个有序的子文件R[low..m]和R[m+1..high]归并成一个有序的*/
    /*子文件R[low..high]*/
    int i=low;
    int j=m+1;
    int p=0;    /*置初始值*/
    int *R1=NULL;

    if ((R1=(int* )malloc((high-low+1)*sizeof (int )))==NULL)
    {
        puts("Insufficient memory available!");/*如果分配空间失败*/
        exit(0);
    }

    while (i<=m&&j<=high)/*两子文件非空时取其小者输出到R1[p]上*/
        R1[p++]=(R[i]<=R[j])?R[i++]:R[j++];

    while (i<=m)/*若第一个子文件非空,则复制剩余记录到R1中*/
        R1[p++]=R[i++];

    while (j<=high)/*若第二个子文件非空,则复制剩余记录到R2中*/
        R1[p++]=R[j++];

    for (p=0,i=low;i<=high;p++,i++)
        R[i]=R1[p];/*归并完毕后将复制结果放回*/

    free(R1);
}

void Merge_SortDC(int low,int high)
{
    /*用分治法对R[low..high]进行二路归并排序*/
    int mid=0;

    if (low<high)
    {
        mid=(low+high)/2;/*分解*/

        Merge_SortDC(low,mid);/*递归地对R[low,mid]排序*/

        Merge_SortDC(mid+1,high);/*递归地对R[mid+1,high]排序*/

        Merge(low,mid,high);/*组合,将两个有序区归并为一个有序区*/
    }
}