题解 | #牛牛学数列#
牛牛学数列
http://www.nowcoder.com/practice/0b97367cd2184c12a0e02f7c223aee11
#include<stdio.h>
int main()
{
int i =0,sum=0;
scanf("%d",&i);
for(int j =1;j<=i;j++)
{
if(j%2==0)
sum-=j;
else
sum+=j;
}
printf("%d\n",sum);
return 0;
}