#include #include #include #include #include #include #include #define REP(i, a, b) for (int i = int(a); i < int(b); i++) using namespace std; using ll = long long int; using P = pair; // clang-format off #ifdef _DEBUG_ #define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false) template void PPPPP(T t) { cerr << t; } template void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); } #else #define dump(...) do{ } while(false) #endif template vector make_v(size_t a, T b) { return vector(a, b); } template auto make_v(size_t a, Ts... ts) { return vector(a, make_v(ts...)); } template bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; } template bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; } template void print(T a) { cout << a << endl; } template void print(T a, Ts... ts) { cout << a << ' '; print(ts...); } template istream &operator,(istream &in, T &t) { return in >> t; } // clang-format on #include int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n; cin, n; vector x(n); REP(i, 0, n) { cin, x[i]; } double xySum = 0, xSum = 0, ySum = 0, xxSum = 0; REP(i, 0, n) { xySum += i * x[i]; xSum += i; ySum += x[i]; xxSum += i * i; } double a = (n * xySum - xSum * ySum) / (n * xxSum - xSum * xSum); double b = (xxSum * ySum - xySum * xSum) / (n * xxSum - xSum * xSum); double cost = 0.0; REP(i, 0, n) { double y = a * i + b; cost += (y - x[i]) * (y - x[i]); } cout << fixed << setprecision(15) << b << " " << a << endl; cout << fixed << setprecision(15) << cost << endl; return 0; }