题解 | 牛牛学数列
牛牛学数列
https://www.nowcoder.com/practice/0b97367cd2184c12a0e02f7c223aee11
#include<bits/stdc++.h>
using namespace std;
int main(){
int n,sum=0;
cin>>n;
for(int i=1;i<=n;i++){
if(i%2==0){
sum-=i;
}else{sum+=i;
}
}cout<<sum<<endl;return 0;
}
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