POJ 2661 预处理

Factstone Benchmark

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 2335		Accepted: 1259

Description

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?

Input

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.

Output

For each test case, output a line giving the Factstone rating.

Sample Input

1960
1981
0

Sample Output

3
8

Source

Waterloo local 2005.09.24

哥至今仍然没有想明白，为什么C++提交会CE。。。。。

Source Code

Problem: 2661		User: bingshen
Memory: 8232K		Time: 94MS
Language: G++		Result: Accepted

• Source Code

  #include<stdio.h>
  #include<math.h>
  
  double a[1000001];
  
  void init()
  {
  	int i;
  	a[1]=log(1);
  	for(i=2;i<=1000000;i++)
  	{
  		a[i]=a[i-1]+((log(i))/(log(2)));
  	}
  }
  
  int main()
  {
  	init();
  	int n,i;
  	double num;
  	while(scanf("%d",&n)!=EOF)
  	{
  		if(n==0)
  			break;
  		num=4.0*pow(2,((n-1960)/10));
  		for(i=1;i<=1000000;i++)
  		{
  			if(a[i]>num)
  			{
  				break;
  			}
  		}
  		printf("%d/n",i-1);
  	}
  	return 0;
  }