题解 | #牛牛学数列#
牛牛学数列
https://www.nowcoder.com/practice/0b97367cd2184c12a0e02f7c223aee11
#include <stdio.h>
int main()
{
int a = 0;
int flag = 1;//设置一个标志
scanf("%d",&a);
int i = 0;
int sum = 0;
for(i = 1;i<=a;i++)
{
sum +=flag*i;
flag = -flag;//奇数为正,偶为负
}
printf("%d",sum);
return 0;
}
