ZOJ-3693

坑爹的精度问题。。到最后也没搞懂最后加个0.0049是干吗的，％.2lf明明是已经是四舍五入了啊。。无语

#include<stdio.h>#include<math.h>int main(){int n, k;double w;while (scanf("%d %lf %d", &n, &w, &k) != EOF)printf("%.2lf\n", 0.0049 + ((n + 2) - (n + 2) / k) * w / 2);return 0;}