UVA - 10014 Simple calculations
题目大意:给一个公式 a0 an+1 和c的全家求a1
解题思路:推公式得a1 = (n*a0 + an_1 - 2*s)/(n+1);
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int main () {
int N;
int n;
int t = 1;
double c[10000];
double a0,a1,an_1;
scanf("%d", &N);
while (N--) {
double s = 0;
scanf("%d%lf%lf", &n, &a0, &an_1);
for (int i = 1; i <= n; i++) {
scanf("%lf", &c[i]);
s += (n-i+1)*c[i];
}
a1 = (n*a0 + an_1 - 2*s)/(n+1);
if (t != 1) printf("\n");
t++;
printf("%.2lf\n", a1);
}
}