内存:128  时间:1

题目描述

Amtel has announced that it will release a 128-bit computer chip by 2010, a 256-bit computer by 2020, and so on, continuing its strategy of doubling the word-size every ten years. (Amtel released a 64-bit computer in 2000, a 32-bit computer in 1990, a 16-bit computer in 1980, an 8-bit computer in 1970, and a 4-bit computer, its first, in 1960.)

Amtel will use a new benchmark – the Factstone – to advertise the vastly improved capacity of its new chips. The Factstone rating is defined to be the largest integer n such that n! can be represented as an unsigned integer in a computer word.

Given a year 1960 ≤ y ≤ 2160, what will be the Factstone rating of Amtel’s most recently released chip?

There are several test cases. For each test case, there is one line of input containing y. A line containing 0 follows the last test case. For each test case, output a line giving the Factstone rating.

 

输入

输出

样例输入

1960
1981
0

样例输出

3
8

提示

代码如下

#include<stdio.h>
#include<math.h>
int main()
{
	int y,i;
	double sum;
	while(scanf("%d",&y)!=EOF,y)
	{
		sum=0;
		if(y==1960)
			printf("3\n");
		else
		{
			for(i=1;;i++)
			{
				sum+=log10(i)/log10(2);
				if(sum>pow(2,(y-1960)/10+2))
					break;
			}
			printf("%d\n",i-1);
		}
	}
	return 0;
}

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