HDU1018——Big Number

Big Number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 34866    Accepted Submission(s): 16552

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

21020

 

Sample Output

719

 

解：题目中要求得到N的阶乘的位数，位数就会联想到使用log10进行求解。而log10（5*6）=log10（5）+log10（6），因此不需要求得阶乘最终解，而且根据数据量，只需要一遍循环，做加法即可。

#include<stdio.h>#include<math.h>int main(){long long n;long long x;scanf("%I64d",&n);while(n--){double count=0.0;scanf("%I64d",&x);for(double i=2;i<=x;i++){count+=log10(i);}printf("%I64d\n",(long long)(count+1));}return 0;}