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

196019810

 

Sample Output

38

 

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;}