#define LOCAL #ifdef LOCAL #define _GLIBCXX_DEBUG #endif #include using namespace std; #define rep(i,s,n) for (int i = (ll)s; i < (ll)n; i++) #define rrep(i,n,e) for (int i = (ll)n; i > (ll)e; i--) #define ll long long #define ld long double #define pb push_back #define eb emplace_back #define All(x) x.begin(), x.end() #define Range(x, i, j) x.begin() + i, x.begin() + j #define lbidx(x, y) lower_bound(x.begin(), x.end(), y) - x.begin() #define ubidx(x, y) upper_bound(x.begin(), x.end(), y) - x.begin() #define llbidx(x, y, z) lower_bound(x.begin(), x.end(), z) - lower_bound(x.begin(), x.end(), y) // dist between two elements // #define M_PI 3.14159265358979323846 // CF #define deg2rad(deg) ((((double)deg)/((double)360)*2*M_PI)) #define rad2deg(rad) ((((double)rad)/(double)2/M_PI)*(double)360) #define Find(set, element) set.find(element) != set.end() #define Decimal(x) cout << fixed << setprecision(10) << x << endl; // 小数点を10桁まで表示 #define endl "\n" #define Case(x) printf("Case #%d: ", x); // gcj typedef pair PI; typedef pair PLL; typedef vector vi; typedef vector> vvi; typedef vector>> vvvi; typedef vector vl; typedef vector> vvl; typedef vector>> vvvl; typedef vector vpi; typedef vector> vvpi; typedef vector vpl; typedef vector> vvpl; typedef vector vch; typedef vector> vvch; constexpr ll LINF = 1001002003004005006ll; constexpr int INF = 1001001001; constexpr int n_max = 2e5+10; template inline bool chmax(T &a, T b) { if(a inline bool chmin(T &a, T b) { if(a>b) { a=b; return true; } return false; }; template T POW(T x, U n) {T ret=1; while (n>0) {if (n&1) {ret*=x;} x*=x; n>>=1;} return ret;}; // debug template string to_string(pair p); string to_string(const string &s) {return '"' + s + '"';}; string to_string(const char c) {return to_string((string) &c);}; string to_string(bool b) {return (b ? "true" : "false");}; template string to_string(bitset v){ string res = ""; for(size_t i = 0; i < N; i++) res += static_cast('0' + v[i]); return res; }; template string to_string(A v) { bool first = true; string res = "{"; for(const auto &x : v) { if(!first) res += ", "; first = false; res += to_string(x); } res += "}"; return res; }; template string to_string(pair p){return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";} void debug_out() {cerr << endl;}; template void debug_out(Head H, Tail... T) { cerr << " " << to_string(H); debug_out(T...); }; #ifdef LOCAL #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) #else #define debug(...) 71 #endif void print() { cout << endl; } template void print(Head&& head, Tail&&... tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; print(forward(tail)...); }; template void print(vector &vec) { for (auto& a : vec) { cout << a; if (&a != &vec.back()) cout << " "; } cout << endl; }; template void print(vector> &df) { for (auto& vec : df) { print(vec); } }; template class modint { using i64 = int_fast64_t; public: i64 a; constexpr modint(const i64 x = 0) noexcept { this -> a = x % Modulus; if(a < 0){ a += Modulus; } } // constexpr i64 &value() const noexcept {return a;} constexpr const i64 &value() const noexcept {return a;} constexpr modint operator+(const modint rhs) const noexcept { return modint(*this) += rhs; } constexpr modint operator-(const modint rhs) const noexcept { return modint(*this) -= rhs; } constexpr modint operator*(const modint rhs) const noexcept { return modint(*this) *= rhs; } constexpr modint operator/(const modint rhs) const noexcept { return modint(*this) /= rhs; } constexpr modint &operator+=(const modint rhs) noexcept { a += rhs.a; if(a >= Modulus) { a -= Modulus; } return *this; } constexpr modint &operator-=(const modint rhs) noexcept { if(a < rhs.a) { a += Modulus; } a -= rhs.a; return *this; } constexpr modint &operator*=(const modint rhs) noexcept { a = a * rhs.a % Modulus; return *this; } constexpr modint &operator/=(modint rhs) noexcept { i64 a_ = rhs.a, b = Modulus, u = 1, v = 0; while(b){ i64 t = a_/b; a_ -= t * b; swap(a_,b); u -= t * v; swap(u,v); } a = a * u % Modulus; if(a < 0) a += Modulus; return *this; } constexpr bool operator==(const modint rhs) noexcept { return a == rhs.a; } constexpr bool operator!=(const modint rhs) noexcept { return a != rhs.a; } constexpr bool operator>(const modint rhs) noexcept { return a > rhs.a; } constexpr bool operator>=(const modint rhs) noexcept { return a >= rhs.a; } constexpr bool operator<(const modint rhs) noexcept { return a < rhs.a; } constexpr bool operator<=(const modint rhs) noexcept { return a <= rhs.a; } // constexpr modint& operator++() noexcept { // return (*this) += modint(1); // } // constexpr modint operator++(int) { // modint tmp(*this); // operator++(); // return tmp; // } // constexpr modint& operator--() noexcept { // return (*this) -= modint(1); // } // constexpr modint operator--(int) { // modint tmp(*this); // operator--(); // return tmp; // } template friend constexpr modint modpow(const modint &mt, T n) noexcept { if(n < 0){ modint t = (modint(1) / mt); return modpow(t, -n); } modint res = 1, tmp = mt; while(n){ if(n & 1)res *= tmp; tmp *= tmp; n /= 2; } return res; } }; const long long MOD = 1e9+7; using mint = modint; // iostream std::ostream &operator<<(std::ostream &out, const modint &m) { out << m.a; return out; }; std::istream &operator>>(std::istream &in, modint &m) { long long a; in >> a; m = mint(a); return in; }; mint fact[200005]; void init() { fact[0] = mint(1); for(int i = 1; i < 200005; i++) { fact[i] = fact[i-1] * mint(i); } }; // calculate nCr mod mint modcomb(long long n, long long r) { return fact[n] / fact[r] / fact[n - r]; }; int main() { ios::sync_with_stdio(false); cin.tie(0); int N; cin >> N; vector A(N); rep(i, 0, N) cin >> A[i]; init(); mint ans = mint(0); rep(i, 0, N) { ans += A[i] * modcomb(N-1, i); } cout << ans << endl; return 0; };