题解 | #牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include <stdio.h>
#include <math.h>
int main()
{
int n=0;
scanf("%d",&n);
double sum=0;
double sum1=0;
for(int i=1;i<=n;i++)
{
int m=1;
if(i%2==0)
m=-1;
sum1+=m*(2*i-1);
sum+=1.0/sum1;
}
printf("%.3lf",sum);
return 0;
}
