1.2插入排序-折半插入排序_r5-1折半插入排序。-优快云博客

1.2插入排序-折半插入排序

/* Binary Insertion Sort*/

一.评估

稳定的排序算法

时间复杂度O(n^2)

移动次数最小值n-1,最大值(n+2)(n-1)/2，平均值（n^2）/4。

与直接插入相比较少了比较的次数。

二.思想

逐一插入，折半比较。

r[0]作用：哨兵（监视哨）、暂存器。

void BiInsertSort(int *r)
{
	int i,j,high,low,m;

	for(i = 2; i <= N; i ++)
	{
		r[0] = r[i];<span style="white-space:pre">	</span>//r[0]为哨兵、暂存器

		low = 1;
		high = i-1;
		while(low <= high)//查找插入点
		{
			m = (low + high)/2;
			if(r[0] < r[m])
				high = m-1;
			else
				low = m+1;
		}

		for(j = i-1;j >= high+1;j --)
		{
			r[j+1] = r[j];
		}

		r[high+1] = r[0];
	}
}

三.示例

/* Binary Insertion Sort*/
<span class="comment" style="background-color: inherit; line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; color: rgb(0, 130, 0);">//Copyright @wangwei14309 All rights reservd</span><span style="background-color: inherit; color: black; line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none;">  </span>
         
# include <stdio.h>
void creat(int *r);
void BiInsertSort(int *r);
void print(int *r);
int N;
int main()
{
	int a[50];
	
	creat(a);

	BiInsertSort(a);

	print(a);
}

void creat(int *r)
{
	int i;
	printf("sort how many numbers :");
	scanf("%d",&N);
	printf("input %d numbers :",N);
	for(i = 1;i <= N;i ++)
	{
		scanf("%d",&r[i]);
	}
}

void BiInsertSort(int *r)
{
	int i,j,high,low,m;

	for(i = 2; i <= N; i ++)
	{
		r[0] = r[i];//r[0]为哨兵、暂存器

		low = 1;
		high = i-1;
		while(low <= high)//查找插入点
		{
			m = (low + high)/2;
			if(r[0] < r[m])
				high = m-1;
			else
				low = m+1;
		}

		for(j = i-1;j >= high+1;j --)
		{
			r[j+1] = r[j];
		}

		r[high+1] = r[0];
	}
}

void print(int *r)
{
	int i;

	printf("the result is :");
	for(i = 1;i <= N;i ++)
		printf("%d ",r[i]);
	printf("\n");

}