hdu1012-u Calculate e

http://acm.hdu.edu.cn/showproblem.php?pid=1012

如题，求出n属于0 ~  9 之间所有满足公式的解

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<algorithm>#include<bitset>#include<stdlib.h>#include<iomanip> using namespace std;int main(){int n ;double e ;cout<< "n e" << endl ;      cout<< "- -----------" << endl ;    cout<< "0 1" << endl ;    cout<< "1 2" << endl ;    cout<< "2 2.5" << endl ;    n = 2 ; e = 2.5 ;for( int i = 3 ; i <= 9 ; i++ ){n *= i ;e += 1.0 / n ;printf( "%d %.9lf\n" , i , e ) ; } return 0 ;}