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  1. #include <iostream>
  2. #include <cmath>
  3. using namespace std;
  4.  
  5. int main() {
  6. double a, sum;
  7. int n;
  8. cin >> n;
  9. sum = 0;
  10. for(int i = 0; i < n; i++)
  11. {
  12. cin >> a;
  13. sum += a;
  14. }
  15. cout << 2*sum*sum;
  16. return 0;
  17. }
Success #stdin #stdout 0s 3476KB
stdin
4
0.5 2.5 -0.7 2.6

stdout
48.02