C语言分治法实现归并排序

#include "stdio.h"
#define MAX 100
int is1[MAX],is2[MAX];//原数组is1，临时空间数组is2
void merge(int low,int mid,int high){
  int i=low,j=mid+1,k=low;
  while(i<=mid&&j<=high)
    if(is1[i]<is1[j])
      is2[k++]=is1[i++];
    else
      is2[k++]=is1[j++];
  while(i<=mid)
    is2[k++]=is1[i++];
  while (j<=high)
    is2[k++]=is1[j++];
  for ( i = low; i <=high ; i++) {
    is1[i]=is2[i];
    printf("%5d",is1[i]);
  }
  printf("\n");
}
 
void mergeSort(int a, int b){
  if(a<b){
    int mid=(a+b)/2;
    mergeSort(a,mid);
    mergeSort(mid+1,b);
    merge(a,mid,b);
  }
}
 
void main(){
  int i,n;
  printf("请输入元素个数：");
  scanf("%d",&n);
  printf("请依次输入每个元素：\n");
  for ( i = 1; i <=n ; ++i) {
    scanf("%d",&is1[i]);
  }
  mergeSort(1,n);
  printf("排序后的序列为：\n");
  for ( i = 1; i <=n ; ++i) {
    printf("%4d",is1[i]);
  }
}