3259. Mysterious Number

最新推荐文章于 2024-09-25 11:53:33 发布

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最新推荐文章于 2024-09-25 11:53:33 发布

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本文链接：https://blog.youkuaiyun.com/u010643814/article/details/38799725

本文介绍了一种算法，用于计算特定范围内神秘数字的数量。神秘数字是指能被其所有不同因数数量整除的数字。文章提供了完整的代码实现，并通过样例输入输出展示了算法的有效性。

Mysterious Number refers to a number which can be divisible by the number of distinct factors that it has. For instance, 1 (1 factor), 12 (6 factors) and 9 (3 factors) are Mysterious Numbers, but 7(2 factors) or 16 (5 factors) are not.

Given two integers low and high, please calculate the number of Mysterious Numbers between low and high, inclusive.

Input

For each test case, there are two integers low and high in one line separated by spaces. 1 ≤ low ≤ high ≤ 1,000,000

Output

Print out the number of Mysterious Numbers between low and high, inclusive.

Sample Input

1 10
10 15

Sample Output

4
1
#include<stdio.h>
#include<cstring>
const int num=1000001;
int a[num],b[num];
void f(){
	memset(a,0,sizeof(a));
	a[1]=1;
	for(int i=2;i<num;i++)
	{
		if(!a[i])
		{
			a[i]=2;
			for(int j=i+i;j<num;j=j+i)
			{
				a[j]=a[j]+1;
			}
		}
		else
		{
			a[i]=a[i]+2;
			for(int j=i+i;j<num;j=j+i)
				a[j]=a[j]+1;
		}
	}
	b[0]=0;
	for(int i=1;i<num;i++)
	{
		if(i%a[i]==0)
			b[i]=1;
		b[i]=b[i]+b[i-1];
	}
}
int main(){
	int low,high,r;
	f();
	while(scanf("%d%d",&low,&high)!=EOF){
		
		printf("%d\n",b[high]-b[low-1]);
	}	
	return 0;
}