#include #ifdef _MSC_VER # include #else # include #endif #include #include namespace suisen { // ! utility template using constraints_t = std::enable_if_t, std::nullptr_t>; template constexpr decltype(auto) constexpr_if(Then&& then, OrElse&& or_else) { if constexpr (cond_v) { return std::forward(then); } else { return std::forward(or_else); } } // ! function template using is_same_as_invoke_result = std::is_same, ReturnType>; template using is_uni_op = is_same_as_invoke_result; template using is_bin_op = is_same_as_invoke_result; template using is_comparator = std::is_same, bool>; // ! integral template >> constexpr int bit_num = std::numeric_limits>::digits; template struct is_nbit { static constexpr bool value = bit_num == n; }; template static constexpr bool is_nbit_v = is_nbit::value; // ? template struct safely_multipliable {}; template <> struct safely_multipliable { using type = long long; }; template <> struct safely_multipliable { using type = __int128_t; }; template <> struct safely_multipliable { using type = unsigned long long; }; template <> struct safely_multipliable { using type = __uint128_t; }; template <> struct safely_multipliable { using type = __uint128_t; }; template <> struct safely_multipliable { using type = float; }; template <> struct safely_multipliable { using type = double; }; template <> struct safely_multipliable { using type = long double; }; template using safely_multipliable_t = typename safely_multipliable::type; template struct rec_value_type { using type = T; }; template struct rec_value_type> { using type = typename rec_value_type::type; }; template using rec_value_type_t = typename rec_value_type::type; } // namespace suisen // ! type aliases using i128 = __int128_t; using u128 = __uint128_t; template using pq_greater = std::priority_queue, std::greater>; // ! macros (internal) #define DETAIL_OVERLOAD2(_1,_2,name,...) name #define DETAIL_OVERLOAD3(_1,_2,_3,name,...) name #define DETAIL_OVERLOAD4(_1,_2,_3,_4,name,...) name #define DETAIL_REP4(i,l,r,s) for(std::remove_reference_t>i=(l);i<(r);i+=(s)) #define DETAIL_REP3(i,l,r) DETAIL_REP4(i,l,r,1) #define DETAIL_REP2(i,n) DETAIL_REP3(i,0,n) #define DETAIL_REPINF3(i,l,s) for(std::remove_reference_t>i=(l);;i+=(s)) #define DETAIL_REPINF2(i,l) DETAIL_REPINF3(i,l,1) #define DETAIL_REPINF1(i) DETAIL_REPINF2(i,0) #define DETAIL_RREP4(i,l,r,s) for(std::remove_reference_t>i=(l)+fld((r)-(l)-1,s)*(s);i>=(l);i-=(s)) #define DETAIL_RREP3(i,l,r) DETAIL_RREP4(i,l,r,1) #define DETAIL_RREP2(i,n) DETAIL_RREP3(i,0,n) #define DETAIL_CAT_I(a, b) a##b #define DETAIL_CAT(a, b) DETAIL_CAT_I(a, b) #define DETAIL_UNIQVAR(tag) DETAIL_CAT(tag, __LINE__) // ! macros #define REP(...) DETAIL_OVERLOAD4(__VA_ARGS__, DETAIL_REP4 , DETAIL_REP3 , DETAIL_REP2 )(__VA_ARGS__) #define RREP(...) DETAIL_OVERLOAD4(__VA_ARGS__, DETAIL_RREP4 , DETAIL_RREP3 , DETAIL_RREP2 )(__VA_ARGS__) #define REPINF(...) DETAIL_OVERLOAD3(__VA_ARGS__, DETAIL_REPINF3, DETAIL_REPINF2, DETAIL_REPINF1)(__VA_ARGS__) #define LOOP(n) for (std::remove_reference_t> DETAIL_UNIQVAR(loop_variable) = n; DETAIL_UNIQVAR(loop_variable) --> 0;) #define ALL(iterable) std::begin(iterable), std::end(iterable) #define INPUT(type, ...) type __VA_ARGS__; read(__VA_ARGS__) // ! debug #ifdef LOCAL # define debug(...) debug_internal(#__VA_ARGS__, __VA_ARGS__) template void debug_internal(const char* s, T&& first, Args&&... args) { constexpr const char* prefix = "[\033[32mDEBUG\033[m] "; constexpr const char* open_brakets = sizeof...(args) == 0 ? "" : "("; constexpr const char* close_brakets = sizeof...(args) == 0 ? "" : ")"; std::cerr << prefix << open_brakets << s << close_brakets << ": " << open_brakets << std::forward(first); ((std::cerr << ", " << std::forward(args)), ...); std::cerr << close_brakets << "\n"; } #else # define debug(...) void(0) #endif // ! I/O utilities // __int128_t std::ostream& operator<<(std::ostream& dest, __int128_t value) { std::ostream::sentry s(dest); if (s) { __uint128_t tmp = value < 0 ? -value : value; char buffer[128]; char* d = std::end(buffer); do { --d; *d = "0123456789"[tmp % 10]; tmp /= 10; } while (tmp != 0); if (value < 0) { --d; *d = '-'; } int len = std::end(buffer) - d; if (dest.rdbuf()->sputn(d, len) != len) { dest.setstate(std::ios_base::badbit); } } return dest; } // __uint128_t std::ostream& operator<<(std::ostream& dest, __uint128_t value) { std::ostream::sentry s(dest); if (s) { char buffer[128]; char* d = std::end(buffer); do { --d; *d = "0123456789"[value % 10]; value /= 10; } while (value != 0); int len = std::end(buffer) - d; if (dest.rdbuf()->sputn(d, len) != len) { dest.setstate(std::ios_base::badbit); } } return dest; } // pair template std::ostream& operator<<(std::ostream& out, const std::pair& a) { return out << a.first << ' ' << a.second; } // tuple template std::ostream& operator<<(std::ostream& out, const std::tuple& a) { if constexpr (N >= std::tuple_size_v>) return out; else { out << std::get(a); if constexpr (N + 1 < std::tuple_size_v>) out << ' '; return operator<<(out, a); } } // vector template std::ostream& operator<<(std::ostream& out, const std::vector& a) { for (auto it = a.begin(); it != a.end();) { out << *it; if (++it != a.end()) out << ' '; } return out; } // array template std::ostream& operator<<(std::ostream& out, const std::array& a) { for (auto it = a.begin(); it != a.end();) { out << *it; if (++it != a.end()) out << ' '; } return out; } inline void print() { std::cout << '\n'; } template inline void print(const Head& head, const Tail &...tails) { std::cout << head; if (sizeof...(tails)) std::cout << ' '; print(tails...); } template auto print_all(const Iterable& v, std::string sep = " ", std::string end = "\n") -> decltype(std::cout << *v.begin(), void()) { for (auto it = v.begin(); it != v.end();) { std::cout << *it; if (++it != v.end()) std::cout << sep; } std::cout << end; } __int128_t stoi128(const std::string& s) { __int128_t ret = 0; for (int i = 0; i < int(s.size()); i++) if ('0' <= s[i] and s[i] <= '9') ret = 10 * ret + s[i] - '0'; if (s[0] == '-') ret = -ret; return ret; } __uint128_t stou128(const std::string& s) { __uint128_t ret = 0; for (int i = 0; i < int(s.size()); i++) if ('0' <= s[i] and s[i] <= '9') ret = 10 * ret + s[i] - '0'; return ret; } // __int128_t std::istream& operator>>(std::istream& in, __int128_t& v) { std::string s; in >> s; v = stoi128(s); return in; } // __uint128_t std::istream& operator>>(std::istream& in, __uint128_t& v) { std::string s; in >> s; v = stou128(s); return in; } // pair template std::istream& operator>>(std::istream& in, std::pair& a) { return in >> a.first >> a.second; } // tuple template std::istream& operator>>(std::istream& in, std::tuple& a) { if constexpr (N >= std::tuple_size_v>) return in; else return operator>>(in >> std::get(a), a); } // vector template std::istream& operator>>(std::istream& in, std::vector& a) { for (auto it = a.begin(); it != a.end(); ++it) in >> *it; return in; } // array template std::istream& operator>>(std::istream& in, std::array& a) { for (auto it = a.begin(); it != a.end(); ++it) in >> *it; return in; } template void read(Args &...args) { (std::cin >> ... >> args); } // ! integral utilities // Returns pow(-1, n) template constexpr inline int pow_m1(T n) { return -(n & 1) | 1; } // Returns pow(-1, n) template <> constexpr inline int pow_m1(bool n) { return -int(n) | 1; } // Returns floor(x / y) template constexpr inline T fld(const T x, const T y) { return (x ^ y) >= 0 ? x / y : (x - (y + pow_m1(y >= 0))) / y; } template constexpr inline T cld(const T x, const T y) { return (x ^ y) <= 0 ? x / y : (x + (y + pow_m1(y >= 0))) / y; } template >, std::nullptr_t> = nullptr> __attribute__((target("popcnt"))) constexpr inline int popcount(const T x) { return _mm_popcnt_u32(x); } template , std::nullptr_t> = nullptr> __attribute__((target("popcnt"))) constexpr inline int popcount(const T x) { return _mm_popcnt_u64(x); } template >, std::nullptr_t> = nullptr> constexpr inline int count_lz(const T x) { return x ? __builtin_clz(x) : suisen::bit_num; } template , std::nullptr_t> = nullptr> constexpr inline int count_lz(const T x) { return x ? __builtin_clzll(x) : suisen::bit_num; } template >, std::nullptr_t> = nullptr> constexpr inline int count_tz(const T x) { return x ? __builtin_ctz(x) : suisen::bit_num; } template , std::nullptr_t> = nullptr> constexpr inline int count_tz(const T x) { return x ? __builtin_ctzll(x) : suisen::bit_num; } template constexpr inline int floor_log2(const T x) { return suisen::bit_num - 1 - count_lz(x); } template constexpr inline int ceil_log2(const T x) { return floor_log2(x) + ((x & -x) != x); } template constexpr inline int kth_bit(const T x, const unsigned int k) { return (x >> k) & 1; } template constexpr inline int parity(const T x) { return popcount(x) & 1; } // ! container template auto priqueue_comp(const Comparator comparator) { return std::priority_queue, Comparator>(comparator); } template void sort_unique_erase(Container& a) { std::sort(a.begin(), a.end()); a.erase(std::unique(a.begin(), a.end()), a.end()); } template auto foreach_adjacent_values(InputIterator first, InputIterator last, BiConsumer f) -> decltype(f(*first++, *last), void()) { if (first != last) for (auto itr = first, itl = itr++; itr != last; itl = itr++) f(*itl, *itr); } template auto foreach_adjacent_values(Container &&c, BiConsumer f) -> decltype(c.begin(), c.end(), void()) { foreach_adjacent_values(c.begin(), c.end(), f); } // ! other utilities // x <- min(x, y). returns true iff `x` has chenged. template inline bool chmin(T& x, const T& y) { return y >= x ? false : (x = y, true); } // x <- max(x, y). returns true iff `x` has chenged. template inline bool chmax(T& x, const T& y) { return y <= x ? false : (x = y, true); } template , std::nullptr_t> = nullptr> std::string bin(T val, int bit_num = -1) { std::string res; if (bit_num != -1) { for (int bit = bit_num; bit-- > 0;) res += '0' + ((val >> bit) & 1); } else { for (; val; val >>= 1) res += '0' + (val & 1); std::reverse(res.begin(), res.end()); } return res; } template , std::nullptr_t> = nullptr> std::vector digits_low_to_high(T val, T base = 10) { std::vector res; for (; val; val /= base) res.push_back(val % base); if (res.empty()) res.push_back(T{ 0 }); return res; } template , std::nullptr_t> = nullptr> std::vector digits_high_to_low(T val, T base = 10) { auto res = digits_low_to_high(val, base); std::reverse(res.begin(), res.end()); return res; } template std::string join(const std::vector& v, const std::string& sep, const std::string& end) { std::ostringstream ss; for (auto it = v.begin(); it != v.end();) { ss << *it; if (++it != v.end()) ss << sep; } ss << end; return ss.str(); } template auto transform_to_vector(const Func &f, const Seq &s) { std::vector> v; v.reserve(std::size(s)), std::transform(std::begin(s), std::end(s), std::back_inserter(v), f); return v; } template auto copy_to_vector(const Seq &s) { std::vector v; v.reserve(std::size(s)), std::copy(std::begin(s), std::end(s), std::back_inserter(v)); return v; } template Seq concat(Seq s, const Seq &t) { s.reserve(std::size(s) + std::size(t)); std::copy(std::begin(t), std::end(t), std::back_inserter(s)); return s; } template std::vector split(const Seq s, typename Seq::value_type delim) { std::vector res; for (auto itl = std::begin(s), itr = itl;; itl = ++itr) { while (itr != std::end(s) and *itr != delim) ++itr; res.emplace_back(itl, itr); if (itr == std::end(s)) return res; } } int digit_to_int(char c) { return c - '0'; } int lowercase_to_int(char c) { return c - 'a'; } int uppercase_to_int(char c) { return c - 'A'; } std::vector digit_str_to_ints(const std::string &s) { return transform_to_vector(digit_to_int, s); } std::vector lowercase_str_to_ints(const std::string &s) { return transform_to_vector(lowercase_to_int, s); } std::vector uppercase_str_to_ints(const std::string &s) { return transform_to_vector(uppercase_to_int, s); } const std::string Yes = "Yes", No = "No", YES = "YES", NO = "NO"; namespace suisen {} using namespace suisen; using namespace std; struct io_setup { io_setup(int precision = 10) { std::ios::sync_with_stdio(false); std::cin.tie(nullptr); std::cout << std::fixed << std::setprecision(precision); } } io_setup_ {}; // ! code from here #include #include #include namespace suisen { namespace default_operator { template auto zero() -> decltype(T { 0 }) { return T { 0 }; } template auto one() -> decltype(T { 1 }) { return T { 1 }; } template auto add(const T &x, const T &y) -> decltype(x + y) { return x + y; } template auto sub(const T &x, const T &y) -> decltype(x - y) { return x - y; } template auto mul(const T &x, const T &y) -> decltype(x * y) { return x * y; } template auto div(const T &x, const T &y) -> decltype(x / y) { return x / y; } template auto mod(const T &x, const T &y) -> decltype(x % y) { return x % y; } template auto neg(const T &x) -> decltype(-x) { return -x; } template auto inv(const T &x) -> decltype(one() / x) { return one() / x; } } // default_operator namespace default_operator_noref { template auto zero() -> decltype(T { 0 }) { return T { 0 }; } template auto one() -> decltype(T { 1 }) { return T { 1 }; } template auto add(T x, T y) -> decltype(x + y) { return x + y; } template auto sub(T x, T y) -> decltype(x - y) { return x - y; } template auto mul(T x, T y) -> decltype(x * y) { return x * y; } template auto div(T x, T y) -> decltype(x / y) { return x / y; } template auto mod(T x, T y) -> decltype(x % y) { return x % y; } template auto neg(T x) -> decltype(-x) { return -x; } template auto inv(T x) -> decltype(one() / x) { return one() / x; } } // default_operator } // namespace suisen namespace suisen { template < typename T, size_t N, size_t M, T(*_add)(T, T) = default_operator_noref::add, T(*_neg)(T) = default_operator_noref::neg, T(*_zero)() = default_operator_noref::zero, T(*_mul)(T, T) = default_operator_noref::mul, T(*_inv)(T) = default_operator_noref::inv, T(*_one)() = default_operator_noref::one > struct ArrayMatrix : public std::array, N> { private: enum Operator { Add, Mul }; template static constexpr bool is_square_v = N == M; template using MatrixType = ArrayMatrix; public: using base_type = std::array, N>; using container_type = base_type; using row_type = std::array; using base_type::base_type; ArrayMatrix() : ArrayMatrix(_zero()) {} ArrayMatrix(T fill_value) { for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) (*this)[i][j] = fill_value; } ArrayMatrix(const container_type& c) : base_type{ c } {} ArrayMatrix(const std::initializer_list& c) { assert(c.size() == N); size_t i = 0; for (const auto& row : c) { for (size_t j = 0; j < M; ++j) (*this)[i][j] = row[j]; ++i; } } static ArrayMatrix e0() { return ArrayMatrix(Operator::Add); } static MatrixType e1() { return MatrixType(Operator::Mul); } int size() const { static_assert(is_square_v<>); return N; } std::pair shape() const { return { N, M }; } int row_size() const { return N; } int col_size() const { return M; } ArrayMatrix operator+() const { return *this; } ArrayMatrix operator-() const { ArrayMatrix A; for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) A[i][j] = _neg((*this)[i][j]); return A; } friend ArrayMatrix& operator+=(ArrayMatrix& A, const ArrayMatrix& B) { for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) A[i][j] = _add(A[i][j], B[i][j]); return A; } friend ArrayMatrix& operator-=(ArrayMatrix& A, const ArrayMatrix& B) { for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) A[i][j] = _add(A[i][j], _neg(B[i][j])); return A; } template friend MatrixType& operator*=(ArrayMatrix& A, const MatrixType& B) { return A = A * B; } friend ArrayMatrix& operator*=(ArrayMatrix& A, const T& val) { for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) A[i][j] = _mul(A[i][j], val); return A; } friend ArrayMatrix& operator/=(ArrayMatrix& A, const ArrayMatrix& B) { static_assert(is_square_v<>); return A *= *B.inv(); } friend ArrayMatrix& operator/=(ArrayMatrix& A, const T& val) { return A *= _inv(val); } friend ArrayMatrix operator+(ArrayMatrix A, const ArrayMatrix& B) { A += B; return A; } friend ArrayMatrix operator-(ArrayMatrix A, const ArrayMatrix& B) { A -= B; return A; } template friend MatrixType operator*(const ArrayMatrix& A, const MatrixType& B) { MatrixType C; for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) for (size_t k = 0; k < K; ++k) C[i][k] = _add(C[i][k], _mul(A[i][j], B[j][k])); return C; } friend ArrayMatrix operator*(ArrayMatrix A, const T& val) { A *= val; return A; } friend ArrayMatrix operator*(const T& val, ArrayMatrix A) { A *= val; return A; } friend std::array operator*(const ArrayMatrix& A, const std::array& x) { std::array b; b.fill(_zero()); for (size_t i = 0; i < N; ++i) for (size_t j = 0; j < M; ++j) b[i] = _add(b[i], _mul(A[i][j], x[j])); return b; } friend ArrayMatrix operator/(ArrayMatrix A, const ArrayMatrix& B) { static_assert(is_square_v<>); return A * B.inv(); } friend ArrayMatrix operator/(ArrayMatrix A, const T& val) { A /= val; return A; } friend ArrayMatrix operator/(const T& val, ArrayMatrix A) { return A.inv() *= val; } ArrayMatrix pow(long long b) const { static_assert(is_square_v<>); assert(b >= 0); ArrayMatrix res(e1()), p(*this); for (; b; b >>= 1) { if (b & 1) res *= p; p *= p; } return res; } std::optional safe_inv() const { static_assert(is_square_v<>); std::array, N> data; for (size_t i = 0; i < N; ++i) { for (size_t j = 0; j < N; ++j) { data[i][j] = (*this)[i][j]; data[i][N + j] = i == j ? _one() : _zero(); } } for (size_t i = 0; i < N; ++i) { for (size_t k = i; k < N; ++k) if (data[k][i] != _zero()) { data[i].swap(data[k]); T c = _inv(data[i][i]); for (size_t j = i; j < 2 * N; ++j) data[i][j] = _mul(c, data[i][j]); break; } if (data[i][i] == _zero()) return std::nullopt; for (size_t k = 0; k < N; ++k) if (k != i and data[k][i] != _zero()) { T c = data[k][i]; for (size_t j = i; j < 2 * N; ++j) data[k][j] = _add(data[k][j], _neg(_mul(c, data[i][j]))); } } ArrayMatrix res; for (size_t i = 0; i < N; ++i) std::copy(data[i].begin() + N, data[i].begin() + 2 * N, res[i].begin()); return res; } ArrayMatrix inv() const { return *safe_inv(); } T det() const { static_assert(is_square_v<>); ArrayMatrix A = *this; bool sgn = false; for (size_t j = 0; j < N; ++j) for (size_t i = j + 1; i < N; ++i) if (A[i][j] != _zero()) { std::swap(A[j], A[i]); T q = _mul(A[i][j], _inv(A[j][j])); for (size_t k = j; k < N; ++k) A[i][k] = _add(A[i][k], _neg(_mul(A[j][k], q))); sgn = not sgn; } T res = sgn ? _neg(_one()) : _one(); for (size_t i = 0; i < N; ++i) res = _mul(res, A[i][i]); return res; } T det_arbitrary_mod() const { static_assert(is_square_v<>); ArrayMatrix A = *this; bool sgn = false; for (size_t j = 0; j < N; ++j) for (size_t i = j + 1; i < N; ++i) { for (; A[i][j].val(); sgn = not sgn) { std::swap(A[j], A[i]); T q = A[i][j].val() / A[j][j].val(); for (size_t k = j; k < N; ++k) A[i][k] -= A[j][k] * q; } } T res = sgn ? -1 : +1; for (size_t i = 0; i < N; ++i) res *= A[i][i]; return res; } private: ArrayMatrix(Operator op) : ArrayMatrix(_zero()) { if (op == Operator::Mul) for (size_t i = 0; i < N; ++i) (*this)[i][i] = _one(); } }; template < typename T, size_t N, T(*_add)(T, T) = default_operator_noref::add, T(*_neg)(T) = default_operator_noref::neg, T(*_zero)() = default_operator_noref::zero, T(*_mul)(T, T) = default_operator_noref::mul, T(*_inv)(T) = default_operator_noref::inv, T(*_one)() = default_operator_noref::one > using SquareArrayMatrix = ArrayMatrix; } // namespace suisen using matrix = ArrayMatrix; int main() { int n; read(n); string s; read(s); s += '#'; constexpr double P = 1. / 3.; vector ans(n); matrix M{ { 1, 0, 0, 0, 0 }, { 0, 1, 0, 0, 0 }, { 0, 0, 1, 0, 0 }, { 0, 0, 0, 1, 0 }, { 0, 0, 0, 0, 1 } }; for (int x = n - 2; x >= 0; --x) { array y = M * array{ 0, 1, 0, 1, 1 }; double a = 0, b = 1; a += P; if (s[x + 1] == '#') { a += P; } else { a += P * y[0]; b += P * y[1]; } if (s[x + 2] == '#') { a += P; } else { a += P * y[2]; b += P * y[3]; } ans[x] = b / (1 - a); matrix A{ { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, P * ans[x] + 1 }, { 1, 0, 0, 0, 0 }, { 0, 1, 0, 0, 0 }, { 0, 0, 0, 0, 1 } }; if (s[x + 1] == '#') { A[0][4] += P; } else { A[0][0] += P; A[1][1] += P; } if (s[x + 2] == '#') { A[0][4] += P; } else { A[0][2] += P; A[1][3] += P; } M = A * M; } print(ans[0] - 1.); return 0; }