题解 | #牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
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#刷题#
#include<iostream> #include<iomanip> using namespace std; int main() { int n,sum=0,flag=1; double sum1=0; cin>>n; for(int i=1;i<=n;i++) { sum+=(2*i-1)*flag; flag*=-1; sum1 +=1.00/sum; } cout<<fixed<<setprecision(3)<<sum1<<endl; return 0; }
#刷题#