p1423.cpp

大概POJ上50道比较难的题的代码

#include <iostream>
#include <cmath>
using namespace std;
const double PI = acos(-1.0);
const double e = exp(1.0);
int main(){
	int N;
	cin >> N;
	while(N--){
		double x,ans;
		cin >> x;
		if(x > 100000)
			ans = x * (log10(x) - log10(e)) + (log10(x) + log10(2.0 * PI)) / 2.0 + log10(1.0+1.0/(12.0*x) + 1.0 / (288.0*x*x));
		else{
			ans = 0.0;
			for(int i = 1;i <= int(x);++i) ans += log10(double(i));
		}
		if(int(ans) <= ans) ans = int(ans + 1.0);
		printf("%d\n",int(ans));
	}
}