HDU 1012 u Calculate e【暴力打表，水】

u Calculate e

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 46844    Accepted Submission(s): 21489

Problem Description

A simple mathematical formula for e is



where n is allowed to go to infinity. This can actually yield very accurate approximations of e using relatively small values of n.

 

 

Output

Output the approximations of e generated by the above formula for the values of n from 0 to 9. The beginning of your output should appear similar to that shown below.

 

 

Sample Output

n e

- -----------

0 1

1 2

2 2.5

3 2.666666667

4 2.708333333

 

 

Source

Greater New York 2000

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

分析：暴力打表就好了，因为数据范围只有10个，按照格式打出来就好了，一个简单的求阶层的题目！

下面给出AC代码：

#include <bits/stdc++.h>
using namespace std;
inline double gcd(int n)
{
    int sum=1;
    for(int i=1;i<=n;i++)
        sum*=i;
    return sum;
}
int main()
{
    cout<<'n'<<" "<<'e'<<endl;
    cout<<"- -----------"<<endl;
    cout<<0<<" "<<1<<endl;
    cout<<1<<" "<<2<<endl;
    cout<<2<<" "<<2.5<<endl;
    double sum=2.5;
    for(int i=3;i<=9;i++)
    {
        sum+=(1.0/(double)gcd(i));
        printf("%d %.9lf\n",i,sum);
    }
    return 0;
}