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