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