51 Nod 1130 N的階乘的長度 V2（斯特林近似）

#include<iostream>
#include<cstdio>
#include<cmath>
const double pi=acos(-1);
const double e=2.718281828459;
typedef long long ll;
using namespace std;
int main(){
    int t;
    scanf("%d",&t);
    for(int i=0;i<t;i++){
        ll n;
        scanf("%lld",&n);
        ll ans=0;
        ans=0.5*log10(2.0*pi*n)+1.0*n*log10(1.0*n/exp(1.0))+1;
        printf("%lld\n",ans);
    } 
}