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; int sum=0,i; scanf("%d", &n); for (i = 1; i <= n; i++) { if (i % 2 == 1) { sum += i; } else { sum -= i; } } printf("%d\n", sum); return 0; }