/** * code generated by JHelper * More info: https://github.com/AlexeyDmitriev/JHelper * @author */ #include using namespace std; using ll = long long; using ld = long double; template using P = pair; template using V = vector; using VI = vector; using VL = vector; //#pragma GCC optimize("O3") //#pragma GCC target("avx2") //#pragma GCC target("avx512f") //#pragma GCC optimize("unroll-loops") //#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") //#pragma GCC optimize("Ofast") #define G(size_1) vector>(size_1, vector()) #define SZ(x) ((long long)(x).size()) #define READ ({long long t;cin >> t;t;}) #define FOR(i, __begin, __end) for (auto i = (__begin) - ((__begin) > (__end)); i != (__end) - ((__begin) > (__end)); i += 1 - 2 * ((__begin) > (__end))) #define REP(i, __end) for (auto i = decltype(__end){0}; i < (__end); ++i) #define ALL(x) (x).begin(),(x).end() #define RALL(x) (x).rbegin(),(x).rend() #define F first #define S second #define y0 y3487465 #define y1 y8687969 #define j0 j1347829 #define j1 j234892 #define BIT(n) (1LL<<(n)) #define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() ) #define EB emplace_back #define PB push_back #define fcout cout << fixed << setprecision(12) #define fcerr cerr << fixed << setprecision(12) #define print(x) cout << (x) << '\n' #define printE(x) cout << (x) << endl; #define fprint(x) cout << fixed << setprecision(12) << (x) << '\n' # define BYE(a) do { cout << (a) << endl; return ; } while (false) #define LB lower_bound #define UB upper_bound #define LBI(c, x) distance((c).begin(), lower_bound((c).begin(), (c).end(), (x))) #define UBI(c, x) distance((c).begin(), upper_bound((c).begin(), (c).end(), (x))) #ifdef DEBUG #define DBG(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator _it(_ss); _err(cerr,_it, args); } #define ERR(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator _it(_ss); _err(std::cerr,_it, args); } #else #define DBG(args...) {}; #define ERR(args...) {}; #endif void _err(std::ostream& cerr, istream_iterator it){cerr << endl;} template void _err(std::ostream& cerr, istream_iterator it, T a, Args... args){ cerr << *it << " = " << a << " "; _err(cerr, ++it, args...); } namespace aux{ template struct seq{ }; template struct gen_seq : gen_seq{ }; template struct gen_seq<0, Is...> : seq{ }; template void print_tuple(std::basic_ostream& os, Tuple const& t, seq){ using swallow = int[]; (void) swallow{0, (void(os << (Is == 0 ? "" : ",") << std::get(t)), 0)...}; } template void read_tuple(std::basic_istream& os, Tuple& t, seq){ using swallow = int[]; (void) swallow{0, (void(os >> std::get(t)), 0)...}; } } // aux:: template auto operator<<(std::basic_ostream& os, std::tuple const& t) -> std::basic_ostream&{ os << "("; aux::print_tuple(os, t, aux::gen_seq()); return os << ")"; } template auto operator>>(std::basic_istream& os, std::tuple& t) -> std::basic_istream&{ aux::read_tuple(os, t, aux::gen_seq()); return os; } template inline bool chmax(T& a, const T& b){ if(a < b){ a = b; return 1; } return 0; } template inline bool chmin(T& a, const T& b){ if(b < a){ a = b; return 1; } return 0; } template istream& operator>>(istream& is, pair& V){ is >> V.F >> V.S; return is; } template istream& operator>>(istream& is, vector& V){ for(auto&& ele : V)is >> ele; return is; } template ostream& operator<<(ostream& os, const vector V){ os << "["; int cnt = 0; T curr; if(!V.empty()){ for(int i = 0; i < V.size() - 1; ++i){ if(V[i] == curr)cnt++; else cnt = 0; if(cnt == 4)os << "... "; if(cnt < 4) os << i << ":" << V[i] << " "; curr = V[i]; } os << V.size() - 1 << ":" << V.back(); } os << "]\n"; return os; } template ostream& operator<<(ostream& os, const pair P){ os << "("; os << P.first << "," << P.second; os << ")"; return os; } template ostream& operator<<(ostream& os, const set V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const unordered_set V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const multiset V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << *it << " "; it++; } os << *it; } os << "}"; return os; } template ostream& operator<<(ostream& os, const map V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << "("; os << it->first << "," << it->second; os << ") "; it++; } os << "("; os << it->first << "," << it->second; os << ")"; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const unordered_map V){ os << "{"; if(!V.empty()){ auto it = V.begin(); for(int i = 0; i < V.size() - 1; ++i){ os << "("; os << it->first << "," << it->second; os << ") "; it++; } os << "("; os << it->first << "," << it->second; os << ")"; } os << "}\n"; return os; } template ostream& operator<<(ostream& os, const deque V){ os << "["; if(!V.empty()){ for(int i = 0; i < V.size() - 1; ++i){ os << V[i] << "->"; } if(!V.empty())os << V.back(); } os << "]\n"; return os; }; template ostream& operator<<(ostream& os, const priority_queue V){ priority_queue _V = V; os << "["; if(!_V.empty()){ while(_V.size() > 1){ os << _V.top() << "->"; _V.pop(); } os << _V.top(); } os << "]\n"; return os; }; template struct y_combinator{ F f; // the lambda will be stored here // a forwarding operator(): template decltype(auto) operator()(Args&& ... args) const{ // we pass ourselves to f, then the arguments. // the lambda should take the first argument as `auto&& recurse` or similar. return f(*this, std::forward(args)...); } }; // helper function that deduces the type of the lambda: template y_combinator> recursive(F&& f){ return {std::forward(f)}; } struct hash_pair{ template size_t operator()(const pair& p) const{ auto hash1 = hash{}(p.first); auto hash2 = hash{}(p.second); return hash1^hash2; } }; template auto vec(int n, U v){ return std::vector(n, v); } template auto vec(int n, Args... args){ auto val = vec(std::forward(args)...); return std::vector(n, std::move(val)); } const double PI = 2*acos(.0); const int INF = 0x3f3f3f3f; template inline T ceil(T a, T b){return (a + b - 1)/b;} inline long long popcount(ll x){return __builtin_popcountll(x);} template struct mod_int { constexpr static signed MODULO = M; constexpr static unsigned TABLE_SIZE = T; signed x; mod_int() : x(0) {} mod_int(long long y) : x(static_cast(y >= 0 ? y % MODULO : MODULO - (-y) % MODULO)) {} mod_int(int y) : x(y >= 0 ? y % MODULO : MODULO - (-y) % MODULO) {} explicit operator int() const { return x; } explicit operator long long() const { return x; } explicit operator double() const { return x; } mod_int &operator+=(const mod_int &rhs) { if ((x += rhs.x) >= MODULO) x -= MODULO; return *this; } mod_int &operator-=(const mod_int &rhs) { if ((x += MODULO - rhs.x) >= MODULO) x -= MODULO; return *this; } mod_int &operator*=(const mod_int &rhs) { x = static_cast(1LL * x * rhs.x % MODULO); return *this; } mod_int &operator/=(const mod_int &rhs) { x = static_cast((1LL * x * rhs.inv().x) % MODULO); return *this; } mod_int operator-() const { return mod_int(-x); } mod_int operator+(const mod_int &rhs) const { return mod_int(*this) += rhs; } mod_int operator-(const mod_int &rhs) const { return mod_int(*this) -= rhs; } mod_int operator*(const mod_int &rhs) const { return mod_int(*this) *= rhs; } mod_int operator/(const mod_int &rhs) const { return mod_int(*this) /= rhs; } bool operator<(const mod_int &rhs) const { return x < rhs.x; } mod_int inv() const { assert(x != 0); if (x <= static_cast(TABLE_SIZE)) { if (_inv[1].x == 0) prepare(); return _inv[x]; } else { signed a = x, b = MODULO, u = 1, v = 0, t; while (b) { t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } return mod_int(u); } } mod_int pow(long long t) const { assert(!(x == 0 && t == 0)); mod_int e = *this, res = mod_int(1); for (; t; e *= e, t >>= 1) if (t & 1) res *= e; return res; } mod_int fact() { if (_fact[0].x == 0) prepare(); return _fact[x]; } mod_int inv_fact() { if (_fact[0].x == 0) prepare(); return _inv_fact[x]; } mod_int choose(mod_int y) { assert(y.x <= x); return this->fact() * y.inv_fact() * mod_int(x - y.x).inv_fact(); } static mod_int _inv[TABLE_SIZE + 1]; static mod_int _fact[TABLE_SIZE + 1]; static mod_int _inv_fact[TABLE_SIZE + 1]; static void prepare() { _inv[1] = 1; for (int i = 2; i <= (int)TABLE_SIZE; ++i) { _inv[i] = 1LL * _inv[MODULO % i].x * (MODULO - MODULO / i) % MODULO; } _fact[0] = 1; for (unsigned i = 1; i <= TABLE_SIZE; ++i) { _fact[i] = _fact[i - 1] * int(i); } _inv_fact[TABLE_SIZE] = _fact[TABLE_SIZE].inv(); for (int i = (int)TABLE_SIZE - 1; i >= 0; --i) { _inv_fact[i] = _inv_fact[i + 1] * (i + 1); } } }; template std::ostream &operator<<(std::ostream &os, const mod_int &rhs) { return os << rhs.x; } template std::istream &operator>>(std::istream &is, mod_int &rhs) { long long s; is >> s; rhs = mod_int(s); return is; } template mod_int mod_int::_inv[TABLE_SIZE + 1]; template mod_int mod_int::_fact[TABLE_SIZE + 1]; template mod_int mod_int::_inv_fact[TABLE_SIZE + 1]; template bool operator==(const mod_int &lhs, const mod_int &rhs) { return lhs.x == rhs.x; } template bool operator!=(const mod_int &lhs, const mod_int &rhs) { return !(lhs == rhs); } constexpr int MF = 1000010; constexpr int MOD = 1000000007; //constexpr int MOD = 998244353; using mint = mod_int; mint binom(int n, int r) { return (r < 0 || r > n || n < 0) ? 0 : mint(n).choose(r); } mint fact(int n) { return mint(n).fact(); } mint inv_fact(int n) { return mint(n).inv_fact(); } void solve(std::istream& cin, std::ostream& cout, std::ostream& cerr){ auto solve = [&](){ int N;cin >> N; VI a(N);cin>> a; mint ans = 0; REP(i,N)ans = ans*a[i]+ans+a[i]; print(ans); }; int testcases; cin >> testcases; for(int case_num = 1; case_num <= testcases; case_num++){ solve(); } } #undef int int main() { istream& in(cin); ostream& out(cout); ostringstream err; in.tie(0); ios::sync_with_stdio(0); solve(in, out, err); return 0; }