妙趣横生算法 6：希尔排序

 

1、算法原理

 

http://www.tyut.edu.cn/kecheng1/site01/suanfayanshi/shell_sort.asp 算法演示

 

 

2、程序代码

#include <stdio.h>
#define MAX 255
int R[MAX];
void ShellPass(int d,int n)
{/*希尔排序中的一趟排序，d为当前增量*/
	int i,j;
	for(i=d+1;i<=n;i++)
	{
		if(R[i]<R[i-d])
		{
			R[0]=R[i];
			j=i-d;/*R[0]只是暂存单元，不是哨兵*/
			do
			{/*查找R[i]的插入位置*/
				R[j+d]=R[j];/*后移记录*/
				j=j-d;/*查找前一记录*/
			}while(j>0&&R[0]<R[j]);
			R[j+d]=R[0];/*插入R[i]到正确的位置上*/
		}
	}
}
void Shell_Sort(int n)
{
	int increment=n;/*增量初值，设n>0*/
	do
	{
		increment=increment/3+1;/*求下一增量*/
		ShellPass(increment,n);/*一躺增量为increment的shell插入排序*/
	}while(increment>1);
}
int main()
{
	int i,n;
	printf("Please input total element number of the sequence:");
	scanf("%d",&n);
	if(n<=0||n>MAX)
	{
		printf("n must more than o and less than %d.\n",MAX);
		exit(0);
	}
	printf("Please input the elements one by one:");
	for(i=1;i<=n;i++)
	{
		scanf("%d",&R[i]);
	}
	printf("The sequence you input is:");
	for(i=1;i<=n;i++)
	{
		printf("%4d",R[i]);
	}
	Shell_Sort(n);
	printf("\n The sequence after shell_sort is:");
	for(i=1;i<=n;i++)
	{
		printf("%4d",R[i]);
	}
	printf("\n Press any key to quit...");
	getchar();
	return 0;
}