题解 | #牛牛学数列#

#include <stdio.h>

int main()
{
    int n = 0;
    scanf("%d", &n);
    if (0 == n % 2)
    {
        printf("%d\n", -(n / 2));//n为偶数时
    }
    else
    {
        printf("%d\n", n - (n / 2));//n为奇数时
    }
    return 0;
}