zoj 1526 Big Number 数学

Big Number

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Time Limit:
10 Seconds      Memory Limit:
32768 KB

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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 <= 10^7 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

看了大师的代码，才知道居然有这种操作，orz，恕我太渣。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
int main(){
    int t,n,i;
    t=_S();
    while(t--){
        n=_S();
        double sum = 0;
        for( i = 2 ; i <= n ; i++ )
            sum += log10(i);
        printf("%d\n",(int)sum+1);
    }
    return 0;
}

出处：http://blog.csdn.net/hdweilao/article/details/48661087