题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=1018
网上有求解的数学公式，
#include<iostream>#include <cmath>using namespace std;int main()
{
int caseNum,i,j,n,count; double sum; while (cin>>caseNum)
{ for (i=0;i<caseNum;++i) { cin>>n; sum = 0.0f; count = 0; for (j=1;j<=n;++j) { sum +=log10f(static_cast<float>(j));
} cout<<static_cast<int>(sum)+1<<endl; } } return 0;
}