HDU ACM 11 2086 A1 = ？

#include <iostream>using namespace std;int main(){int n;double start, Final;double Lu[3002];while (cin >> n && EOF){double q = n;cout << fixed;cout.precision(2);cin >> start >> Final;for (int i = 1; i <= n; i++)cin >> Lu[i];double sum, Hui = 0;for (int i = 1; i <= n; i++)Hui += (n - i + 1) * Lu[i];sum = start * (0.5 * n) + Final/2.0 - Hui;sum /= (0.5 * (n + 1));cout << sum << endl;}return 0;}