uva 10014 Simple calculations（数学推导）

#include<stdio.h>

int main()
{
int T, n, i;
double a, aa, sum, temp, ans;
scanf("%d", &T);
while(T--)
{
scanf("%d", &n);
scanf("%lf", &first);
scanf("%lf", &final);
for(i=1, sum=0; i <= n; ++i)
{
scanf("%lf", &temp);
sum += 2.0 * (n + 1 - i) * temp;
}

ans = n * a + aa - sum;
printf("%.2lf\n", ans / (n+1));

if(T != 0) printf("\n");
}
return 0;
}