第一周ACM练习 Big Number

niangniang~

还是很水，主要是利用了公式，求n阶乘的位数。

Big Number

Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other)

 

Problem Description

In many applications very large integers numbers are required. Some of these applications are using keys for secure transmission of data, encryption, etc. In this problem you are given a number, you have to determine the number of digits in the factorial of the number.

 

Input

Input consists of several lines of integer numbers. The first line contains an integer n, which is the number of cases to be tested, followed by n lines, one integer 1 ≤ n ≤ 10⁷ on each line.

 

Output

The output contains the number of digits in the factorial of the integers appearing in the input.

 

Sample Input

2

10

20

Sample Output

7

19

Source

Asia 2002, Dhaka (Bengal)

#include<iostream>
#include<math.h>

using namespace std;

const double pi=acos(-1);
const double e=2.718;

int main()
{
    int nq;
    cin>>nq;
    for(int i=0;i<nq;i++)
    {
        int num;
        cin>>num;
        long int re;
        re=long int(log10(sqrt(2*num*pi))+num*log10(num/e))+1;
        cout<<re<<endl;
    }
    return 0;
}

完毕~