Factstone Benchmark

Factstone Benchmark

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 1224    Accepted Submission(s): 709

Problem 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?

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.

 

Sample Input

  

   1960
1981
0
  

 

Sample Output

  

   3
8
  

 

Source

University of Waterloo Local Contest 2005.09.24

 

Recommend

Eddy

 

 

#include <stdio.h>
#include<cmath>
int main()
{
    int year;
    int endflag;
    int n;
    double sum;
    while(scanf("%d", &year),year)
    {
        endflag = 1<<((year - 1960) / 10 + 2);
        n = 2;
        sum = 0;
        while(sum <= endflag)
        {
            sum += log(n) / log(2);
            ++n;
        }
        printf("%d\n", n - 2);
    }
    return 0;
}