23，24~~

int n;
scanf("%d", &n);
double T = 0.0;
double S = 0.0;
for (int i = 0; i < n; ++i)
{
double gpa, sc;
scanf("%lf %lf", &gpa, &sc);
T += gpa * sc;
S += sc;
}
double gpa_total = T / S;
printf("%.1f\n", gpa_total);
return 0;
}
bug1:是%。1f not%1.f
收获：pass ，pass

24

int n;
scanf("%d", &n);
int s1, p1, s2, p2, s3, p3;
scanf("%d%d%d%d%d%d", &s1, &p1, &s2, &p2, &s3, &p3);
int cost1 = ((n + s1 - 1) / s1) * p1;
int cost2 = ((n + s2 - 1) / s2) * p2;
int cost3 = ((n + s3 - 1) / s3) * p3;
int min_cost = cost1;
if (cost2 < min_cost)
min_cost = cost2;
if (cost3 < min_cost)
min_cost = cost3;
printf("%d\n", min_cost);
return 0;
}

收获：小学题目，**(n + s1 - 1) / s1)