题解 | #牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include <stdio.h> int main() { int input; int j1=-1; int j2; int sum=0; double all=0; scanf("%d",&input); for(int i=1;i<=input;i++) { j1=j1+2; j2=j1; if(i%2==0) { j2=-j1; } sum=sum+j2; all=all+1.0/sum; } printf("%.3lf",all); return 0; }