1 #include
     
       2 #include
      
        3 #include
       
         4 using namespace std; 5  6 int main() 7 { 8     //freopen("acm.acm","r",stdin); 9     int n;10     int i;11     double * a;12     double * c;13     cin>>n;14     a = new double[n+2];15     c = new double[n];16     17     cin>>a[0]>>a[n+1];18     for(i = 0; i < n; ++ i)19     {20         cin>>c[i];21     }22     a[1] = n*a[0] + a[n+1];23     for(i = 0; i < n; ++ i)24     {25         a[1] -= 2*(n - i)*c[i];26     }27     cout<
        
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