// -*- C++ -*-
//===-------------------------- memory ------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_MEMORY
#define _LIBCPP_MEMORY

/*
    memory synopsis

namespace std
{

struct allocator_arg_t { };
inline constexpr allocator_arg_t allocator_arg = allocator_arg_t();

template <class T, class Alloc> struct uses_allocator;

template <class Ptr>
struct pointer_traits
{
    typedef Ptr pointer;
    typedef <details> element_type;
    typedef <details> difference_type;

    template <class U> using rebind = <details>;

    static pointer pointer_to(<details>);
};

template <class T>
struct pointer_traits<T*>
{
    typedef T* pointer;
    typedef T element_type;
    typedef ptrdiff_t difference_type;

    template <class U> using rebind = U*;

    static pointer pointer_to(<details>) noexcept; // constexpr in C++20
};

template <class T> constexpr T* to_address(T* p) noexcept; // C++20
template <class Ptr> auto to_address(const Ptr& p) noexcept; // C++20

template <class Alloc>
struct allocator_traits
{
    typedef Alloc                        allocator_type;
    typedef typename allocator_type::value_type
                                         value_type;

    typedef Alloc::pointer | value_type* pointer;
    typedef Alloc::const_pointer
          | pointer_traits<pointer>::rebind<const value_type>
                                         const_pointer;
    typedef Alloc::void_pointer
          | pointer_traits<pointer>::rebind<void>
                                         void_pointer;
    typedef Alloc::const_void_pointer
          | pointer_traits<pointer>::rebind<const void>
                                         const_void_pointer;
    typedef Alloc::difference_type
          | pointer_traits<pointer>::difference_type
                                         difference_type;
    typedef Alloc::size_type
          | make_unsigned<difference_type>::type
                                         size_type;
    typedef Alloc::propagate_on_container_copy_assignment
          | false_type                   propagate_on_container_copy_assignment;
    typedef Alloc::propagate_on_container_move_assignment
          | false_type                   propagate_on_container_move_assignment;
    typedef Alloc::propagate_on_container_swap
          | false_type                   propagate_on_container_swap;
    typedef Alloc::is_always_equal
          | is_empty                     is_always_equal;

    template <class T> using rebind_alloc  = Alloc::rebind<U>::other | Alloc<T, Args...>;
    template <class T> using rebind_traits = allocator_traits<rebind_alloc<T>>;

    static pointer allocate(allocator_type& a, size_type n);                          // [[nodiscard]] in C++20
    static pointer allocate(allocator_type& a, size_type n, const_void_pointer hint); // [[nodiscard]] in C++20

    static void deallocate(allocator_type& a, pointer p, size_type n) noexcept;

    template <class T, class... Args>
        static void construct(allocator_type& a, T* p, Args&&... args);

    template <class T>
        static void destroy(allocator_type& a, T* p);

    static size_type max_size(const allocator_type& a); // noexcept in C++14

    static allocator_type
        select_on_container_copy_construction(const allocator_type& a);
};

template <>
class allocator<void>
{
public:
    typedef void*                                 pointer;
    typedef const void*                           const_pointer;
    typedef void                                  value_type;

    template <class _Up> struct rebind {typedef allocator<_Up> other;};
};

template <class T>
class allocator
{
public:
    typedef size_t                                size_type;
    typedef ptrdiff_t                             difference_type;
    typedef T*                                    pointer;
    typedef const T*                              const_pointer;
    typedef typename add_lvalue_reference<T>::type       reference;
    typedef typename add_lvalue_reference<const T>::type const_reference;
    typedef T                                     value_type;

    template <class U> struct rebind {typedef allocator<U> other;};

    constexpr allocator() noexcept;                      // constexpr in C++20
    constexpr allocator(const allocator&) noexcept;      // constexpr in C++20
    template <class U>
      constexpr allocator(const allocator<U>&) noexcept; // constexpr in C++20
    ~allocator();
    pointer address(reference x) const noexcept;
    const_pointer address(const_reference x) const noexcept;
    pointer allocate(size_type, allocator<void>::const_pointer hint = 0);
    void deallocate(pointer p, size_type n) noexcept;
    size_type max_size() const noexcept;
    template<class U, class... Args>
        void construct(U* p, Args&&... args);
    template <class U>
        void destroy(U* p);
};

template <class T, class U>
bool operator==(const allocator<T>&, const allocator<U>&) noexcept;

template <class T, class U>
bool operator!=(const allocator<T>&, const allocator<U>&) noexcept;

template <class OutputIterator, class T>
class raw_storage_iterator
    : public iterator<output_iterator_tag,
                      T,                               // purposefully not C++03
                      ptrdiff_t,                       // purposefully not C++03
                      T*,                              // purposefully not C++03
                      raw_storage_iterator&>           // purposefully not C++03
{
public:
    explicit raw_storage_iterator(OutputIterator x);
    raw_storage_iterator& operator*();
    raw_storage_iterator& operator=(const T& element);
    raw_storage_iterator& operator++();
    raw_storage_iterator  operator++(int);
};

template <class T> pair<T*,ptrdiff_t> get_temporary_buffer(ptrdiff_t n) noexcept;
template <class T> void               return_temporary_buffer(T* p) noexcept;

template <class T> T* addressof(T& r) noexcept;
template <class T> T* addressof(const T&& r) noexcept = delete;

template <class InputIterator, class ForwardIterator>
ForwardIterator
uninitialized_copy(InputIterator first, InputIterator last, ForwardIterator result);

template <class InputIterator, class Size, class ForwardIterator>
ForwardIterator
uninitialized_copy_n(InputIterator first, Size n, ForwardIterator result);

template <class ForwardIterator, class T>
void uninitialized_fill(ForwardIterator first, ForwardIterator last, const T& x);

template <class ForwardIterator, class Size, class T>
ForwardIterator
uninitialized_fill_n(ForwardIterator first, Size n, const T& x);

template <class T>
void destroy_at(T* location);

template <class ForwardIterator>
 void destroy(ForwardIterator first, ForwardIterator last);

template <class ForwardIterator, class Size>
 ForwardIterator destroy_n(ForwardIterator first, Size n);

template <class InputIterator, class ForwardIterator>
 ForwardIterator uninitialized_move(InputIterator first, InputIterator last, ForwardIterator result);

template <class InputIterator, class Size, class ForwardIterator>
 pair<InputIterator,ForwardIterator> uninitialized_move_n(InputIterator first, Size n, ForwardIterator result);

template <class ForwardIterator>
 void uninitialized_value_construct(ForwardIterator first, ForwardIterator last);

template <class ForwardIterator, class Size>
 ForwardIterator uninitialized_value_construct_n(ForwardIterator first, Size n);

template <class ForwardIterator>
 void uninitialized_default_construct(ForwardIterator first, ForwardIterator last);

template <class ForwardIterator, class Size>
 ForwardIterator uninitialized_default_construct_n(ForwardIterator first, Size n);

template <class Y> struct auto_ptr_ref {};      // deprecated in C++11, removed in C++17

template<class X>
class auto_ptr                                  // deprecated in C++11, removed in C++17
{
public:
    typedef X element_type;

    explicit auto_ptr(X* p =0) throw();
    auto_ptr(auto_ptr&) throw();
    template<class Y> auto_ptr(auto_ptr<Y>&) throw();
    auto_ptr& operator=(auto_ptr&) throw();
    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
    ~auto_ptr() throw();

    typename add_lvalue_reference<X>::type operator*() const throw();
    X* operator->() const throw();
    X* get() const throw();
    X* release() throw();
    void reset(X* p =0) throw();

    auto_ptr(auto_ptr_ref<X>) throw();
    template<class Y> operator auto_ptr_ref<Y>() throw();
    template<class Y> operator auto_ptr<Y>() throw();
};

template <class T>
struct default_delete
{
    constexpr default_delete() noexcept = default;
    template <class U> default_delete(const default_delete<U>&) noexcept;

    void operator()(T*) const noexcept;
};

template <class T>
struct default_delete<T[]>
{
    constexpr default_delete() noexcept = default;
    void operator()(T*) const noexcept;
    template <class U> void operator()(U*) const = delete;
};

template <class T, class D = default_delete<T>>
class unique_ptr
{
public:
    typedef see below pointer;
    typedef T element_type;
    typedef D deleter_type;

    // constructors
    constexpr unique_ptr() noexcept;
    explicit unique_ptr(pointer p) noexcept;
    unique_ptr(pointer p, see below d1) noexcept;
    unique_ptr(pointer p, see below d2) noexcept;
    unique_ptr(unique_ptr&& u) noexcept;
    unique_ptr(nullptr_t) noexcept : unique_ptr() { }
    template <class U, class E>
        unique_ptr(unique_ptr<U, E>&& u) noexcept;
    template <class U>
        unique_ptr(auto_ptr<U>&& u) noexcept;       // removed in C++17

    // destructor
    ~unique_ptr();

    // assignment
    unique_ptr& operator=(unique_ptr&& u) noexcept;
    template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u) noexcept;
    unique_ptr& operator=(nullptr_t) noexcept;

    // observers
    typename add_lvalue_reference<T>::type operator*() const;
    pointer operator->() const noexcept;
    pointer get() const noexcept;
    deleter_type& get_deleter() noexcept;
    const deleter_type& get_deleter() const noexcept;
    explicit operator bool() const noexcept;

    // modifiers
    pointer release() noexcept;
    void reset(pointer p = pointer()) noexcept;
    void swap(unique_ptr& u) noexcept;
};

template <class T, class D>
class unique_ptr<T[], D>
{
public:
    typedef implementation-defined pointer;
    typedef T element_type;
    typedef D deleter_type;

    // constructors
    constexpr unique_ptr() noexcept;
    explicit unique_ptr(pointer p) noexcept;
    unique_ptr(pointer p, see below d) noexcept;
    unique_ptr(pointer p, see below d) noexcept;
    unique_ptr(unique_ptr&& u) noexcept;
    unique_ptr(nullptr_t) noexcept : unique_ptr() { }

    // destructor
    ~unique_ptr();

    // assignment
    unique_ptr& operator=(unique_ptr&& u) noexcept;
    unique_ptr& operator=(nullptr_t) noexcept;

    // observers
    T& operator[](size_t i) const;
    pointer get() const noexcept;
    deleter_type& get_deleter() noexcept;
    const deleter_type& get_deleter() const noexcept;
    explicit operator bool() const noexcept;

    // modifiers
    pointer release() noexcept;
    void reset(pointer p = pointer()) noexcept;
    void reset(nullptr_t) noexcept;
    template <class U> void reset(U) = delete;
    void swap(unique_ptr& u) noexcept;
};

template <class T, class D>
    void swap(unique_ptr<T, D>& x, unique_ptr<T, D>& y) noexcept;

template <class T1, class D1, class T2, class D2>
    bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
template <class T1, class D1, class T2, class D2>
    bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
template <class T1, class D1, class T2, class D2>
    bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
template <class T1, class D1, class T2, class D2>
    bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
template <class T1, class D1, class T2, class D2>
    bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
template <class T1, class D1, class T2, class D2>
    bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);

template <class T, class D>
    bool operator==(const unique_ptr<T, D>& x, nullptr_t) noexcept;
template <class T, class D>
    bool operator==(nullptr_t, const unique_ptr<T, D>& y) noexcept;
template <class T, class D>
    bool operator!=(const unique_ptr<T, D>& x, nullptr_t) noexcept;
template <class T, class D>
    bool operator!=(nullptr_t, const unique_ptr<T, D>& y) noexcept;

template <class T, class D>
    bool operator<(const unique_ptr<T, D>& x, nullptr_t);
template <class T, class D>
    bool operator<(nullptr_t, const unique_ptr<T, D>& y);
template <class T, class D>
    bool operator<=(const unique_ptr<T, D>& x, nullptr_t);
template <class T, class D>
    bool operator<=(nullptr_t, const unique_ptr<T, D>& y);
template <class T, class D>
    bool operator>(const unique_ptr<T, D>& x, nullptr_t);
template <class T, class D>
    bool operator>(nullptr_t, const unique_ptr<T, D>& y);
template <class T, class D>
    bool operator>=(const unique_ptr<T, D>& x, nullptr_t);
template <class T, class D>
    bool operator>=(nullptr_t, const unique_ptr<T, D>& y);

class bad_weak_ptr
    : public std::exception
{
    bad_weak_ptr() noexcept;
};

template<class T, class... Args> unique_ptr<T> make_unique(Args&&... args);     // C++14
template<class T>                unique_ptr<T> make_unique(size_t n);           // C++14
template<class T, class... Args> unspecified   make_unique(Args&&...) = delete; // C++14, T == U[N]

template<class E, class T, class Y, class D>
    basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, unique_ptr<Y, D> const& p);

template<class T>
class shared_ptr
{
public:
    typedef T element_type;
    typedef weak_ptr<T> weak_type; // C++17

    // constructors:
    constexpr shared_ptr() noexcept;
    template<class Y> explicit shared_ptr(Y* p);
    template<class Y, class D> shared_ptr(Y* p, D d);
    template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
    template <class D> shared_ptr(nullptr_t p, D d);
    template <class D, class A> shared_ptr(nullptr_t p, D d, A a);
    template<class Y> shared_ptr(const shared_ptr<Y>& r, T *p) noexcept;
    shared_ptr(const shared_ptr& r) noexcept;
    template<class Y> shared_ptr(const shared_ptr<Y>& r) noexcept;
    shared_ptr(shared_ptr&& r) noexcept;
    template<class Y> shared_ptr(shared_ptr<Y>&& r) noexcept;
    template<class Y> explicit shared_ptr(const weak_ptr<Y>& r);
    template<class Y> shared_ptr(auto_ptr<Y>&& r);          // removed in C++17
    template <class Y, class D> shared_ptr(unique_ptr<Y, D>&& r);
    shared_ptr(nullptr_t) : shared_ptr() { }

    // destructor:
    ~shared_ptr();

    // assignment:
    shared_ptr& operator=(const shared_ptr& r) noexcept;
    template<class Y> shared_ptr& operator=(const shared_ptr<Y>& r) noexcept;
    shared_ptr& operator=(shared_ptr&& r) noexcept;
    template<class Y> shared_ptr& operator=(shared_ptr<Y>&& r);
    template<class Y> shared_ptr& operator=(auto_ptr<Y>&& r); // removed in C++17
    template <class Y, class D> shared_ptr& operator=(unique_ptr<Y, D>&& r);

    // modifiers:
    void swap(shared_ptr& r) noexcept;
    void reset() noexcept;
    template<class Y> void reset(Y* p);
    template<class Y, class D> void reset(Y* p, D d);
    template<class Y, class D, class A> void reset(Y* p, D d, A a);

    // observers:
    T* get() const noexcept;
    T& operator*() const noexcept;
    T* operator->() const noexcept;
    long use_count() const noexcept;
    bool unique() const noexcept;
    explicit operator bool() const noexcept;
    template<class U> bool owner_before(shared_ptr<U> const& b) const noexcept;
    template<class U> bool owner_before(weak_ptr<U> const& b) const noexcept;
};

// shared_ptr comparisons:
template<class T, class U>
    bool operator==(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
template<class T, class U>
    bool operator!=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
template<class T, class U>
    bool operator<(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
template<class T, class U>
    bool operator>(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
template<class T, class U>
    bool operator<=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
template<class T, class U>
    bool operator>=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;

template <class T>
    bool operator==(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
    bool operator==(nullptr_t, const shared_ptr<T>& y) noexcept;
template <class T>
    bool operator!=(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
    bool operator!=(nullptr_t, const shared_ptr<T>& y) noexcept;
template <class T>
    bool operator<(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
bool operator<(nullptr_t, const shared_ptr<T>& y) noexcept;
template <class T>
    bool operator<=(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
    bool operator<=(nullptr_t, const shared_ptr<T>& y) noexcept;
template <class T>
    bool operator>(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
    bool operator>(nullptr_t, const shared_ptr<T>& y) noexcept;
template <class T>
    bool operator>=(const shared_ptr<T>& x, nullptr_t) noexcept;
template <class T>
    bool operator>=(nullptr_t, const shared_ptr<T>& y) noexcept;

// shared_ptr specialized algorithms:
template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>& b) noexcept;

// shared_ptr casts:
template<class T, class U>
    shared_ptr<T> static_pointer_cast(shared_ptr<U> const& r) noexcept;
template<class T, class U>
    shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const& r) noexcept;
template<class T, class U>
    shared_ptr<T> const_pointer_cast(shared_ptr<U> const& r) noexcept;

// shared_ptr I/O:
template<class E, class T, class Y>
    basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, shared_ptr<Y> const& p);

// shared_ptr get_deleter:
template<class D, class T> D* get_deleter(shared_ptr<T> const& p) noexcept;

template<class T, class... Args>
    shared_ptr<T> make_shared(Args&&... args);
template<class T, class A, class... Args>
    shared_ptr<T> allocate_shared(const A& a, Args&&... args);

template<class T>
class weak_ptr
{
public:
    typedef T element_type;

    // constructors
    constexpr weak_ptr() noexcept;
    template<class Y> weak_ptr(shared_ptr<Y> const& r) noexcept;
    weak_ptr(weak_ptr const& r) noexcept;
    template<class Y> weak_ptr(weak_ptr<Y> const& r) noexcept;
    weak_ptr(weak_ptr&& r) noexcept;                      // C++14
    template<class Y> weak_ptr(weak_ptr<Y>&& r) noexcept; // C++14

    // destructor
    ~weak_ptr();

    // assignment
    weak_ptr& operator=(weak_ptr const& r) noexcept;
    template<class Y> weak_ptr& operator=(weak_ptr<Y> const& r) noexcept;
    template<class Y> weak_ptr& operator=(shared_ptr<Y> const& r) noexcept;
    weak_ptr& operator=(weak_ptr&& r) noexcept;                      // C++14
    template<class Y> weak_ptr& operator=(weak_ptr<Y>&& r) noexcept; // C++14

    // modifiers
    void swap(weak_ptr& r) noexcept;
    void reset() noexcept;

    // observers
    long use_count() const noexcept;
    bool expired() const noexcept;
    shared_ptr<T> lock() const noexcept;
    template<class U> bool owner_before(shared_ptr<U> const& b) const noexcept;
    template<class U> bool owner_before(weak_ptr<U> const& b) const noexcept;
};

// weak_ptr specialized algorithms:
template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;

// class owner_less:
template<class T> struct owner_less;

template<class T>
struct owner_less<shared_ptr<T>>
    : binary_function<shared_ptr<T>, shared_ptr<T>, bool>
{
    typedef bool result_type;
    bool operator()(shared_ptr<T> const&, shared_ptr<T> const&) const noexcept;
    bool operator()(shared_ptr<T> const&, weak_ptr<T> const&) const noexcept;
    bool operator()(weak_ptr<T> const&, shared_ptr<T> const&) const noexcept;
};

template<class T>
struct owner_less<weak_ptr<T>>
    : binary_function<weak_ptr<T>, weak_ptr<T>, bool>
{
    typedef bool result_type;
    bool operator()(weak_ptr<T> const&, weak_ptr<T> const&) const noexcept;
    bool operator()(shared_ptr<T> const&, weak_ptr<T> const&) const noexcept;
    bool operator()(weak_ptr<T> const&, shared_ptr<T> const&) const noexcept;
};

template <>  // Added in C++14
struct owner_less<void>
{
    template <class _Tp, class _Up>
    bool operator()( shared_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const noexcept;
    template <class _Tp, class _Up>
    bool operator()( shared_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const noexcept;
    template <class _Tp, class _Up>
    bool operator()(   weak_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const noexcept;
    template <class _Tp, class _Up>
    bool operator()(   weak_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const noexcept;

    typedef void is_transparent;
};

template<class T>
class enable_shared_from_this
{
protected:
    constexpr enable_shared_from_this() noexcept;
    enable_shared_from_this(enable_shared_from_this const&) noexcept;
    enable_shared_from_this& operator=(enable_shared_from_this const&) noexcept;
    ~enable_shared_from_this();
public:
    shared_ptr<T> shared_from_this();
    shared_ptr<T const> shared_from_this() const;
};

template<class T>
    bool atomic_is_lock_free(const shared_ptr<T>* p);
template<class T>
    shared_ptr<T> atomic_load(const shared_ptr<T>* p);
template<class T>
    shared_ptr<T> atomic_load_explicit(const shared_ptr<T>* p, memory_order mo);
template<class T>
    void atomic_store(shared_ptr<T>* p, shared_ptr<T> r);
template<class T>
    void atomic_store_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
template<class T>
    shared_ptr<T> atomic_exchange(shared_ptr<T>* p, shared_ptr<T> r);
template<class T>
    shared_ptr<T>
    atomic_exchange_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
template<class T>
    bool
    atomic_compare_exchange_weak(shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
template<class T>
    bool
    atomic_compare_exchange_strong( shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
template<class T>
    bool
    atomic_compare_exchange_weak_explicit(shared_ptr<T>* p, shared_ptr<T>* v,
                                          shared_ptr<T> w, memory_order success,
                                          memory_order failure);
template<class T>
    bool
    atomic_compare_exchange_strong_explicit(shared_ptr<T>* p, shared_ptr<T>* v,
                                            shared_ptr<T> w, memory_order success,
                                            memory_order failure);
// Hash support
template <class T> struct hash;
template <class T, class D> struct hash<unique_ptr<T, D> >;
template <class T> struct hash<shared_ptr<T> >;

template <class T, class Alloc>
  inline constexpr bool uses_allocator_v = uses_allocator<T, Alloc>::value;

// Pointer safety
enum class pointer_safety { relaxed, preferred, strict };
void declare_reachable(void *p);
template <class T> T *undeclare_reachable(T *p);
void declare_no_pointers(char *p, size_t n);
void undeclare_no_pointers(char *p, size_t n);
pointer_safety get_pointer_safety() noexcept;

void* align(size_t alignment, size_t size, void*& ptr, size_t& space);

}  // std

*/

#include <__config>
#include <type_traits>
#include <typeinfo>
#include <cstddef>
#include <cstdint>
#include <new>
#include <utility>
#include <limits>
#include <iterator>
#include <__functional_base>
#include <iosfwd>
#include <tuple>
#include <stdexcept>
#include <cstring>
#include <cassert>
#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
#  include <atomic>
#endif
#include <version>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>


_LIBCPP_BEGIN_NAMESPACE_STD

template <class _ValueType>
inline _LIBCPP_INLINE_VISIBILITY
_ValueType __libcpp_relaxed_load(_ValueType const* __value) {
#if !defined(_LIBCPP_HAS_NO_THREADS) && \
    defined(__ATOMIC_RELAXED) &&        \
    (__has_builtin(__atomic_load_n) || _GNUC_VER >= 407)
    return __atomic_load_n(__value, __ATOMIC_RELAXED);
#else
    return *__value;
#endif
}

template <class _ValueType>
inline _LIBCPP_INLINE_VISIBILITY
_ValueType __libcpp_acquire_load(_ValueType const* __value) {
#if !defined(_LIBCPP_HAS_NO_THREADS) && \
    defined(__ATOMIC_ACQUIRE) &&        \
    (__has_builtin(__atomic_load_n) || _GNUC_VER >= 407)
    return __atomic_load_n(__value, __ATOMIC_ACQUIRE);
#else
    return *__value;
#endif
}

// addressof moved to <type_traits>

template <class _Tp> class allocator;

template <>
class _LIBCPP_TEMPLATE_VIS allocator<void>
{
public:
    typedef void*             pointer;
    typedef const void*       const_pointer;
    typedef void              value_type;

    template <class _Up> struct rebind {typedef allocator<_Up> other;};
};

template <>
class _LIBCPP_TEMPLATE_VIS allocator<const void>
{
public:
    typedef const void*       pointer;
    typedef const void*       const_pointer;
    typedef const void        value_type;

    template <class _Up> struct rebind {typedef allocator<_Up> other;};
};

// pointer_traits

template <class _Tp, class = void>
struct __has_element_type : false_type {};

template <class _Tp>
struct __has_element_type<_Tp,
              typename __void_t<typename _Tp::element_type>::type> : true_type {};

template <class _Ptr, bool = __has_element_type<_Ptr>::value>
struct __pointer_traits_element_type;

template <class _Ptr>
struct __pointer_traits_element_type<_Ptr, true>
{
    typedef typename _Ptr::element_type type;
};

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
{
    typedef typename _Sp<_Tp, _Args...>::element_type type;
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
{
    typedef _Tp type;
};

#else  // _LIBCPP_HAS_NO_VARIADICS

template <template <class> class _Sp, class _Tp>
struct __pointer_traits_element_type<_Sp<_Tp>, true>
{
    typedef typename _Sp<_Tp>::element_type type;
};

template <template <class> class _Sp, class _Tp>
struct __pointer_traits_element_type<_Sp<_Tp>, false>
{
    typedef _Tp type;
};

template <template <class, class> class _Sp, class _Tp, class _A0>
struct __pointer_traits_element_type<_Sp<_Tp, _A0>, true>
{
    typedef typename _Sp<_Tp, _A0>::element_type type;
};

template <template <class, class> class _Sp, class _Tp, class _A0>
struct __pointer_traits_element_type<_Sp<_Tp, _A0>, false>
{
    typedef _Tp type;
};

template <template <class, class, class> class _Sp, class _Tp, class _A0, class _A1>
struct __pointer_traits_element_type<_Sp<_Tp, _A0, _A1>, true>
{
    typedef typename _Sp<_Tp, _A0, _A1>::element_type type;
};

template <template <class, class, class> class _Sp, class _Tp, class _A0, class _A1>
struct __pointer_traits_element_type<_Sp<_Tp, _A0, _A1>, false>
{
    typedef _Tp type;
};

template <template <class, class, class, class> class _Sp, class _Tp, class _A0,
                                                           class _A1, class _A2>
struct __pointer_traits_element_type<_Sp<_Tp, _A0, _A1, _A2>, true>
{
    typedef typename _Sp<_Tp, _A0, _A1, _A2>::element_type type;
};

template <template <class, class, class, class> class _Sp, class _Tp, class _A0,
                                                           class _A1, class _A2>
struct __pointer_traits_element_type<_Sp<_Tp, _A0, _A1, _A2>, false>
{
    typedef _Tp type;
};

#endif  // _LIBCPP_HAS_NO_VARIADICS

template <class _Tp, class = void>
struct __has_difference_type : false_type {};

template <class _Tp>
struct __has_difference_type<_Tp,
            typename __void_t<typename _Tp::difference_type>::type> : true_type {};

template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
struct __pointer_traits_difference_type
{
    typedef ptrdiff_t type;
};

template <class _Ptr>
struct __pointer_traits_difference_type<_Ptr, true>
{
    typedef typename _Ptr::difference_type type;
};

template <class _Tp, class _Up>
struct __has_rebind
{
private:
    struct __two {char __lx; char __lxx;};
    template <class _Xp> static __two __test(...);
    template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
public:
    static const bool value = sizeof(__test<_Tp>(0)) == 1;
};

template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
struct __pointer_traits_rebind
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Tp::template rebind<_Up> type;
#else
    typedef typename _Tp::template rebind<_Up>::other type;
#endif
};

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
#else
    typedef typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
#endif
};

template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
{
    typedef _Sp<_Up, _Args...> type;
};

#else  // _LIBCPP_HAS_NO_VARIADICS

template <template <class> class _Sp, class _Tp, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Sp<_Tp>::template rebind<_Up> type;
#else
    typedef typename _Sp<_Tp>::template rebind<_Up>::other type;
#endif
};

template <template <class> class _Sp, class _Tp, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp>, _Up, false>
{
    typedef _Sp<_Up> type;
};

template <template <class, class> class _Sp, class _Tp, class _A0, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Sp<_Tp, _A0>::template rebind<_Up> type;
#else
    typedef typename _Sp<_Tp, _A0>::template rebind<_Up>::other type;
#endif
};

template <template <class, class> class _Sp, class _Tp, class _A0, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0>, _Up, false>
{
    typedef _Sp<_Up, _A0> type;
};

template <template <class, class, class> class _Sp, class _Tp, class _A0,
                                         class _A1, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0, _A1>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Sp<_Tp, _A0, _A1>::template rebind<_Up> type;
#else
    typedef typename _Sp<_Tp, _A0, _A1>::template rebind<_Up>::other type;
#endif
};

template <template <class, class, class> class _Sp, class _Tp, class _A0,
                                         class _A1, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0, _A1>, _Up, false>
{
    typedef _Sp<_Up, _A0, _A1> type;
};

template <template <class, class, class, class> class _Sp, class _Tp, class _A0,
                                                class _A1, class _A2, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0, _A1, _A2>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Sp<_Tp, _A0, _A1, _A2>::template rebind<_Up> type;
#else
    typedef typename _Sp<_Tp, _A0, _A1, _A2>::template rebind<_Up>::other type;
#endif
};

template <template <class, class, class, class> class _Sp, class _Tp, class _A0,
                                                class _A1, class _A2, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _A0, _A1, _A2>, _Up, false>
{
    typedef _Sp<_Up, _A0, _A1, _A2> type;
};

#endif  // _LIBCPP_HAS_NO_VARIADICS

template <class _Ptr>
struct _LIBCPP_TEMPLATE_VIS pointer_traits
{
    typedef _Ptr                                                     pointer;
    typedef typename __pointer_traits_element_type<pointer>::type    element_type;
    typedef typename __pointer_traits_difference_type<pointer>::type difference_type;

#ifndef _LIBCPP_CXX03_LANG
    template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
#else
    template <class _Up> struct rebind
        {typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
#endif  // _LIBCPP_CXX03_LANG

private:
    struct __nat {};
public:
    _LIBCPP_INLINE_VISIBILITY
    static pointer pointer_to(typename conditional<is_void<element_type>::value,
                                           __nat, element_type>::type& __r)
        {return pointer::pointer_to(__r);}
};

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
{
    typedef _Tp*      pointer;
    typedef _Tp       element_type;
    typedef ptrdiff_t difference_type;

#ifndef _LIBCPP_CXX03_LANG
    template <class _Up> using rebind = _Up*;
#else
    template <class _Up> struct rebind {typedef _Up* other;};
#endif

private:
    struct __nat {};
public:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    static pointer pointer_to(typename conditional<is_void<element_type>::value,
                                      __nat, element_type>::type& __r) _NOEXCEPT
        {return _VSTD::addressof(__r);}
};

template <class _From, class _To>
struct __rebind_pointer {
#ifndef _LIBCPP_CXX03_LANG
    typedef typename pointer_traits<_From>::template rebind<_To>        type;
#else
    typedef typename pointer_traits<_From>::template rebind<_To>::other type;
#endif
};

// allocator_traits

template <class _Tp, class = void>
struct __has_pointer_type : false_type {};

template <class _Tp>
struct __has_pointer_type<_Tp,
          typename __void_t<typename _Tp::pointer>::type> : true_type {};

namespace __pointer_type_imp
{

template <class _Tp, class _Dp, bool = __has_pointer_type<_Dp>::value>
struct __pointer_type
{
    typedef typename _Dp::pointer type;
};

template <class _Tp, class _Dp>
struct __pointer_type<_Tp, _Dp, false>
{
    typedef _Tp* type;
};

}  // __pointer_type_imp

template <class _Tp, class _Dp>
struct __pointer_type
{
    typedef typename __pointer_type_imp::__pointer_type<_Tp, typename remove_reference<_Dp>::type>::type type;
};

template <class _Tp, class = void>
struct __has_const_pointer : false_type {};

template <class _Tp>
struct __has_const_pointer<_Tp,
            typename __void_t<typename _Tp::const_pointer>::type> : true_type {};

template <class _Tp, class _Ptr, class _Alloc, bool = __has_const_pointer<_Alloc>::value>
struct __const_pointer
{
    typedef typename _Alloc::const_pointer type;
};

template <class _Tp, class _Ptr, class _Alloc>
struct __const_pointer<_Tp, _Ptr, _Alloc, false>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename pointer_traits<_Ptr>::template rebind<const _Tp> type;
#else
    typedef typename pointer_traits<_Ptr>::template rebind<const _Tp>::other type;
#endif
};

template <class _Tp, class = void>
struct __has_void_pointer : false_type {};

template <class _Tp>
struct __has_void_pointer<_Tp,
               typename __void_t<typename _Tp::void_pointer>::type> : true_type {};

template <class _Ptr, class _Alloc, bool = __has_void_pointer<_Alloc>::value>
struct __void_pointer
{
    typedef typename _Alloc::void_pointer type;
};

template <class _Ptr, class _Alloc>
struct __void_pointer<_Ptr, _Alloc, false>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename pointer_traits<_Ptr>::template rebind<void> type;
#else
    typedef typename pointer_traits<_Ptr>::template rebind<void>::other type;
#endif
};

template <class _Tp, class = void>
struct __has_const_void_pointer : false_type {};

template <class _Tp>
struct __has_const_void_pointer<_Tp,
            typename __void_t<typename _Tp::const_void_pointer>::type> : true_type {};

template <class _Ptr, class _Alloc, bool = __has_const_void_pointer<_Alloc>::value>
struct __const_void_pointer
{
    typedef typename _Alloc::const_void_pointer type;
};

template <class _Ptr, class _Alloc>
struct __const_void_pointer<_Ptr, _Alloc, false>
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename pointer_traits<_Ptr>::template rebind<const void> type;
#else
    typedef typename pointer_traits<_Ptr>::template rebind<const void>::other type;
#endif
};

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
_Tp*
__to_raw_pointer(_Tp* __p) _NOEXCEPT
{
    return __p;
}

#if _LIBCPP_STD_VER <= 17
template <class _Pointer>
inline _LIBCPP_INLINE_VISIBILITY
typename pointer_traits<_Pointer>::element_type*
__to_raw_pointer(_Pointer __p) _NOEXCEPT
{
    return _VSTD::__to_raw_pointer(__p.operator->());
}
#else
template <class _Pointer>
inline _LIBCPP_INLINE_VISIBILITY
auto
__to_raw_pointer(const _Pointer& __p) _NOEXCEPT
-> decltype(pointer_traits<_Pointer>::to_address(__p))
{
    return pointer_traits<_Pointer>::to_address(__p);
}

template <class _Pointer, class... _None>
inline _LIBCPP_INLINE_VISIBILITY
auto
__to_raw_pointer(const _Pointer& __p, _None...) _NOEXCEPT
{
    return _VSTD::__to_raw_pointer(__p.operator->());
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY constexpr
_Tp*
to_address(_Tp* __p) _NOEXCEPT
{
    static_assert(!is_function_v<_Tp>, "_Tp is a function type");
    return __p;
}

template <class _Pointer>
inline _LIBCPP_INLINE_VISIBILITY
auto
to_address(const _Pointer& __p) _NOEXCEPT
{
    return _VSTD::__to_raw_pointer(__p);
}
#endif

template <class _Tp, class = void>
struct __has_size_type : false_type {};

template <class _Tp>
struct __has_size_type<_Tp,
               typename __void_t<typename _Tp::size_type>::type> : true_type {};

template <class _Alloc, class _DiffType, bool = __has_size_type<_Alloc>::value>
struct __size_type
{
    typedef typename make_unsigned<_DiffType>::type type;
};

template <class _Alloc, class _DiffType>
struct __size_type<_Alloc, _DiffType, true>
{
    typedef typename _Alloc::size_type type;
};

template <class _Tp, class = void>
struct __has_propagate_on_container_copy_assignment : false_type {};

template <class _Tp>
struct __has_propagate_on_container_copy_assignment<_Tp,
    typename __void_t<typename _Tp::propagate_on_container_copy_assignment>::type>
        : true_type {};

template <class _Alloc, bool = __has_propagate_on_container_copy_assignment<_Alloc>::value>
struct __propagate_on_container_copy_assignment
{
    typedef false_type type;
};

template <class _Alloc>
struct __propagate_on_container_copy_assignment<_Alloc, true>
{
    typedef typename _Alloc::propagate_on_container_copy_assignment type;
};

template <class _Tp, class = void>
struct __has_propagate_on_container_move_assignment : false_type {};

template <class _Tp>
struct __has_propagate_on_container_move_assignment<_Tp,
           typename __void_t<typename _Tp::propagate_on_container_move_assignment>::type>
               : true_type {};

template <class _Alloc, bool = __has_propagate_on_container_move_assignment<_Alloc>::value>
struct __propagate_on_container_move_assignment
{
    typedef false_type type;
};

template <class _Alloc>
struct __propagate_on_container_move_assignment<_Alloc, true>
{
    typedef typename _Alloc::propagate_on_container_move_assignment type;
};

template <class _Tp, class = void>
struct __has_propagate_on_container_swap : false_type {};

template <class _Tp>
struct __has_propagate_on_container_swap<_Tp,
           typename __void_t<typename _Tp::propagate_on_container_swap>::type>
               : true_type {};

template <class _Alloc, bool = __has_propagate_on_container_swap<_Alloc>::value>
struct __propagate_on_container_swap
{
    typedef false_type type;
};

template <class _Alloc>
struct __propagate_on_container_swap<_Alloc, true>
{
    typedef typename _Alloc::propagate_on_container_swap type;
};

template <class _Tp, class = void>
struct __has_is_always_equal : false_type {};

template <class _Tp>
struct __has_is_always_equal<_Tp,
           typename __void_t<typename _Tp::is_always_equal>::type>
               : true_type {};

template <class _Alloc, bool = __has_is_always_equal<_Alloc>::value>
struct __is_always_equal
{
    typedef typename _VSTD::is_empty<_Alloc>::type type;
};

template <class _Alloc>
struct __is_always_equal<_Alloc, true>
{
    typedef typename _Alloc::is_always_equal type;
};

template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
struct __has_rebind_other
{
private:
    struct __two {char __lx; char __lxx;};
    template <class _Xp> static __two __test(...);
    template <class _Xp> static char __test(typename _Xp::template rebind<_Up>::other* = 0);
public:
    static const bool value = sizeof(__test<_Tp>(0)) == 1;
};

template <class _Tp, class _Up>
struct __has_rebind_other<_Tp, _Up, false>
{
    static const bool value = false;
};

template <class _Tp, class _Up, bool = __has_rebind_other<_Tp, _Up>::value>
struct __allocator_traits_rebind
{
    typedef typename _Tp::template rebind<_Up>::other type;
};

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <template <class, class...> class _Alloc, class _Tp, class ..._Args, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, true>
{
    typedef typename _Alloc<_Tp, _Args...>::template rebind<_Up>::other type;
};

template <template <class, class...> class _Alloc, class _Tp, class ..._Args, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, false>
{
    typedef _Alloc<_Up, _Args...> type;
};

#else  // _LIBCPP_HAS_NO_VARIADICS

template <template <class> class _Alloc, class _Tp, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp>, _Up, true>
{
    typedef typename _Alloc<_Tp>::template rebind<_Up>::other type;
};

template <template <class> class _Alloc, class _Tp, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp>, _Up, false>
{
    typedef _Alloc<_Up> type;
};

template <template <class, class> class _Alloc, class _Tp, class _A0, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0>, _Up, true>
{
    typedef typename _Alloc<_Tp, _A0>::template rebind<_Up>::other type;
};

template <template <class, class> class _Alloc, class _Tp, class _A0, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0>, _Up, false>
{
    typedef _Alloc<_Up, _A0> type;
};

template <template <class, class, class> class _Alloc, class _Tp, class _A0,
                                         class _A1, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0, _A1>, _Up, true>
{
    typedef typename _Alloc<_Tp, _A0, _A1>::template rebind<_Up>::other type;
};

template <template <class, class, class> class _Alloc, class _Tp, class _A0,
                                         class _A1, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0, _A1>, _Up, false>
{
    typedef _Alloc<_Up, _A0, _A1> type;
};

template <template <class, class, class, class> class _Alloc, class _Tp, class _A0,
                                                class _A1, class _A2, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0, _A1, _A2>, _Up, true>
{
    typedef typename _Alloc<_Tp, _A0, _A1, _A2>::template rebind<_Up>::other type;
};

template <template <class, class, class, class> class _Alloc, class _Tp, class _A0,
                                                class _A1, class _A2, class _Up>
struct __allocator_traits_rebind<_Alloc<_Tp, _A0, _A1, _A2>, _Up, false>
{
    typedef _Alloc<_Up, _A0, _A1, _A2> type;
};

#endif  // _LIBCPP_HAS_NO_VARIADICS

#ifndef _LIBCPP_CXX03_LANG

template <class _Alloc, class _SizeType, class _ConstVoidPtr>
auto
__has_allocate_hint_test(_Alloc&& __a, _SizeType&& __sz, _ConstVoidPtr&& __p)
    -> decltype((void)__a.allocate(__sz, __p), true_type());

template <class _Alloc, class _SizeType, class _ConstVoidPtr>
auto
__has_allocate_hint_test(const _Alloc& __a, _SizeType&& __sz, _ConstVoidPtr&& __p)
    -> false_type;

template <class _Alloc, class _SizeType, class _ConstVoidPtr>
struct __has_allocate_hint
    : integral_constant<bool,
        is_same<
            decltype(_VSTD::__has_allocate_hint_test(declval<_Alloc>(),
                                          declval<_SizeType>(),
                                          declval<_ConstVoidPtr>())),
            true_type>::value>
{
};

#else  // _LIBCPP_CXX03_LANG

template <class _Alloc, class _SizeType, class _ConstVoidPtr>
struct __has_allocate_hint
    : true_type
{
};

#endif  // _LIBCPP_CXX03_LANG

#if !defined(_LIBCPP_CXX03_LANG)

template <class _Alloc, class _Tp, class ..._Args>
decltype(_VSTD::declval<_Alloc>().construct(_VSTD::declval<_Tp*>(),
                                           _VSTD::declval<_Args>()...),
                                           true_type())
__has_construct_test(_Alloc&& __a, _Tp* __p, _Args&& ...__args);

template <class _Alloc, class _Pointer, class ..._Args>
false_type
__has_construct_test(const _Alloc& __a, _Pointer&& __p, _Args&& ...__args);

template <class _Alloc, class _Pointer, class ..._Args>
struct __has_construct
    : integral_constant<bool,
        is_same<
            decltype(_VSTD::__has_construct_test(declval<_Alloc>(),
                                          declval<_Pointer>(),
                                          declval<_Args>()...)),
            true_type>::value>
{
};

template <class _Alloc, class _Pointer>
auto
__has_destroy_test(_Alloc&& __a, _Pointer&& __p)
    -> decltype(__a.destroy(__p), true_type());

template <class _Alloc, class _Pointer>
auto
__has_destroy_test(const _Alloc& __a, _Pointer&& __p)
    -> false_type;

template <class _Alloc, class _Pointer>
struct __has_destroy
    : integral_constant<bool,
        is_same<
            decltype(_VSTD::__has_destroy_test(declval<_Alloc>(),
                                        declval<_Pointer>())),
            true_type>::value>
{
};

template <class _Alloc>
auto
__has_max_size_test(_Alloc&& __a)
    -> decltype(__a.max_size(), true_type());

template <class _Alloc>
auto
__has_max_size_test(const volatile _Alloc& __a)
    -> false_type;

template <class _Alloc>
struct __has_max_size
    : integral_constant<bool,
        is_same<
            decltype(_VSTD::__has_max_size_test(declval<_Alloc&>())),
            true_type>::value>
{
};

template <class _Alloc>
auto
__has_select_on_container_copy_construction_test(_Alloc&& __a)
    -> decltype(__a.select_on_container_copy_construction(), true_type());

template <class _Alloc>
auto
__has_select_on_container_copy_construction_test(const volatile _Alloc& __a)
    -> false_type;

template <class _Alloc>
struct __has_select_on_container_copy_construction
    : integral_constant<bool,
        is_same<
            decltype(_VSTD::__has_select_on_container_copy_construction_test(declval<_Alloc&>())),
            true_type>::value>
{
};

#else  // _LIBCPP_CXX03_LANG

template <class _Alloc, class _Pointer, class _Tp, class = void>
struct __has_construct : std::false_type {};

template <class _Alloc, class _Pointer, class _Tp>
struct __has_construct<_Alloc, _Pointer, _Tp, typename __void_t<
    decltype(_VSTD::declval<_Alloc>().construct(_VSTD::declval<_Pointer>(), _VSTD::declval<_Tp>()))
>::type> : std::true_type {};

template <class _Alloc, class _Pointer, class = void>
struct __has_destroy : false_type {};

template <class _Alloc, class _Pointer>
struct __has_destroy<_Alloc, _Pointer, typename __void_t<
    decltype(_VSTD::declval<_Alloc>().destroy(_VSTD::declval<_Pointer>()))
>::type> : std::true_type {};

template <class _Alloc>
struct __has_max_size
    : true_type
{
};

template <class _Alloc>
struct __has_select_on_container_copy_construction
    : false_type
{
};

#endif  // _LIBCPP_CXX03_LANG

template <class _Alloc, class _Ptr, bool = __has_difference_type<_Alloc>::value>
struct __alloc_traits_difference_type
{
    typedef typename pointer_traits<_Ptr>::difference_type type;
};

template <class _Alloc, class _Ptr>
struct __alloc_traits_difference_type<_Alloc, _Ptr, true>
{
    typedef typename _Alloc::difference_type type;
};

template <class _Tp>
struct __is_default_allocator : false_type {};

template <class _Tp>
struct __is_default_allocator<_VSTD::allocator<_Tp> > : true_type {};

template <class _Alloc>
struct _LIBCPP_TEMPLATE_VIS allocator_traits
{
    typedef _Alloc                              allocator_type;
    typedef typename allocator_type::value_type value_type;

    typedef typename __pointer_type<value_type, allocator_type>::type pointer;
    typedef typename __const_pointer<value_type, pointer, allocator_type>::type const_pointer;
    typedef typename __void_pointer<pointer, allocator_type>::type void_pointer;
    typedef typename __const_void_pointer<pointer, allocator_type>::type const_void_pointer;

    typedef typename __alloc_traits_difference_type<allocator_type, pointer>::type difference_type;
    typedef typename __size_type<allocator_type, difference_type>::type size_type;

    typedef typename __propagate_on_container_copy_assignment<allocator_type>::type
                     propagate_on_container_copy_assignment;
    typedef typename __propagate_on_container_move_assignment<allocator_type>::type
                     propagate_on_container_move_assignment;
    typedef typename __propagate_on_container_swap<allocator_type>::type
                     propagate_on_container_swap;
    typedef typename __is_always_equal<allocator_type>::type
                     is_always_equal;

#ifndef _LIBCPP_CXX03_LANG
    template <class _Tp> using rebind_alloc =
                  typename __allocator_traits_rebind<allocator_type, _Tp>::type;
    template <class _Tp> using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
#else  // _LIBCPP_CXX03_LANG
    template <class _Tp> struct rebind_alloc
        {typedef typename __allocator_traits_rebind<allocator_type, _Tp>::type other;};
    template <class _Tp> struct rebind_traits
        {typedef allocator_traits<typename rebind_alloc<_Tp>::other> other;};
#endif  // _LIBCPP_CXX03_LANG

    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
    static pointer allocate(allocator_type& __a, size_type __n)
        {return __a.allocate(__n);}
    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
    static pointer allocate(allocator_type& __a, size_type __n, const_void_pointer __hint)
        {return __allocate(__a, __n, __hint,
            __has_allocate_hint<allocator_type, size_type, const_void_pointer>());}

    _LIBCPP_INLINE_VISIBILITY
    static void deallocate(allocator_type& __a, pointer __p, size_type __n) _NOEXCEPT
        {__a.deallocate(__p, __n);}

#ifndef _LIBCPP_HAS_NO_VARIADICS
    template <class _Tp, class... _Args>
        _LIBCPP_INLINE_VISIBILITY
        static void construct(allocator_type& __a, _Tp* __p, _Args&&... __args)
            {__construct(__has_construct<allocator_type, _Tp*, _Args...>(),
                         __a, __p, _VSTD::forward<_Args>(__args)...);}
#else  // _LIBCPP_HAS_NO_VARIADICS
    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static void construct(allocator_type&, _Tp* __p)
            {
                ::new ((void*)__p) _Tp();
            }
    template <class _Tp, class _A0>
        _LIBCPP_INLINE_VISIBILITY
        static void construct(allocator_type& __a, _Tp* __p, const _A0& __a0)
            {
                __construct(__has_construct<allocator_type, _Tp*, const _A0&>(),
                            __a, __p, __a0);
            }
    template <class _Tp, class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        static void construct(allocator_type&, _Tp* __p, const _A0& __a0,
                              const _A1& __a1)
            {
                ::new ((void*)__p) _Tp(__a0, __a1);
            }
    template <class _Tp, class _A0, class _A1, class _A2>
        _LIBCPP_INLINE_VISIBILITY
        static void construct(allocator_type&, _Tp* __p, const _A0& __a0,
                              const _A1& __a1, const _A2& __a2)
            {
                ::new ((void*)__p) _Tp(__a0, __a1, __a2);
            }
#endif  // _LIBCPP_HAS_NO_VARIADICS

    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static void destroy(allocator_type& __a, _Tp* __p)
            {__destroy(__has_destroy<allocator_type, _Tp*>(), __a, __p);}

    _LIBCPP_INLINE_VISIBILITY
    static size_type max_size(const allocator_type& __a) _NOEXCEPT
        {return __max_size(__has_max_size<const allocator_type>(), __a);}

    _LIBCPP_INLINE_VISIBILITY
    static allocator_type
        select_on_container_copy_construction(const allocator_type& __a)
            {return __select_on_container_copy_construction(
                __has_select_on_container_copy_construction<const allocator_type>(),
                __a);}

    template <class _Ptr>
        _LIBCPP_INLINE_VISIBILITY
        static
        void
        __construct_forward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)
        {
            for (; __begin1 != __end1; ++__begin1, (void) ++__begin2)
                construct(__a, _VSTD::__to_raw_pointer(__begin2), _VSTD::move_if_noexcept(*__begin1));
        }

    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static
        typename enable_if
        <
            (__is_default_allocator<allocator_type>::value
                || !__has_construct<allocator_type, _Tp*, _Tp>::value) &&
             is_trivially_move_constructible<_Tp>::value,
            void
        >::type
        __construct_forward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
        {
            ptrdiff_t _Np = __end1 - __begin1;
            if (_Np > 0)
            {
                _VSTD::memcpy(__begin2, __begin1, _Np * sizeof(_Tp));
                __begin2 += _Np;
            }
        }

    template <class _Iter, class _Ptr>
        _LIBCPP_INLINE_VISIBILITY
        static
        void
        __construct_range_forward(allocator_type& __a, _Iter __begin1, _Iter __end1, _Ptr& __begin2)
        {
            for (; __begin1 != __end1; ++__begin1, (void) ++__begin2)
                construct(__a, _VSTD::__to_raw_pointer(__begin2), *__begin1);
        }

    template <class _SourceTp, class _DestTp,
              class _RawSourceTp = typename remove_const<_SourceTp>::type,
              class _RawDestTp = typename remove_const<_DestTp>::type>
        _LIBCPP_INLINE_VISIBILITY
        static
        typename enable_if
        <
            is_trivially_move_constructible<_DestTp>::value &&
            is_same<_RawSourceTp, _RawDestTp>::value &&
            (__is_default_allocator<allocator_type>::value ||
             !__has_construct<allocator_type, _DestTp*, _SourceTp&>::value),
            void
        >::type
        __construct_range_forward(allocator_type&, _SourceTp* __begin1, _SourceTp* __end1, _DestTp*& __begin2)
        {
            ptrdiff_t _Np = __end1 - __begin1;
            if (_Np > 0)
            {
                _VSTD::memcpy(const_cast<_RawDestTp*>(__begin2), __begin1, _Np * sizeof(_DestTp));
                __begin2 += _Np;
            }
        }

    template <class _Ptr>
        _LIBCPP_INLINE_VISIBILITY
        static
        void
        __construct_backward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2)
        {
            while (__end1 != __begin1)
            {
                construct(__a, _VSTD::__to_raw_pointer(__end2-1), _VSTD::move_if_noexcept(*--__end1));
                --__end2;
            }
        }

    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static
        typename enable_if
        <
            (__is_default_allocator<allocator_type>::value
                || !__has_construct<allocator_type, _Tp*, _Tp>::value) &&
             is_trivially_move_constructible<_Tp>::value,
            void
        >::type
        __construct_backward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2)
        {
            ptrdiff_t _Np = __end1 - __begin1;
            __end2 -= _Np;
            if (_Np > 0)
                _VSTD::memcpy(__end2, __begin1, _Np * sizeof(_Tp));
        }

private:

    _LIBCPP_INLINE_VISIBILITY
    static pointer __allocate(allocator_type& __a, size_type __n,
        const_void_pointer __hint, true_type)
        {return __a.allocate(__n, __hint);}
    _LIBCPP_INLINE_VISIBILITY
    static pointer __allocate(allocator_type& __a, size_type __n,
        const_void_pointer, false_type)
        {return __a.allocate(__n);}

#ifndef _LIBCPP_HAS_NO_VARIADICS
    template <class _Tp, class... _Args>
        _LIBCPP_INLINE_VISIBILITY
        static void __construct(true_type, allocator_type& __a, _Tp* __p, _Args&&... __args)
            {__a.construct(__p, _VSTD::forward<_Args>(__args)...);}
    template <class _Tp, class... _Args>
        _LIBCPP_INLINE_VISIBILITY
        static void __construct(false_type, allocator_type&, _Tp* __p, _Args&&... __args)
            {
                ::new ((void*)__p) _Tp(_VSTD::forward<_Args>(__args)...);
            }
#else  // _LIBCPP_HAS_NO_VARIADICS
    template <class _Tp, class _A0>
        _LIBCPP_INLINE_VISIBILITY
        static void __construct(true_type, allocator_type& __a, _Tp* __p,
                                const _A0& __a0)
            {__a.construct(__p, __a0);}
    template <class _Tp, class _A0>
        _LIBCPP_INLINE_VISIBILITY
        static void __construct(false_type, allocator_type&, _Tp* __p,
                                const _A0& __a0)
            {
                ::new ((void*)__p) _Tp(__a0);
            }
#endif  // _LIBCPP_HAS_NO_VARIADICS

    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static void __destroy(true_type, allocator_type& __a, _Tp* __p)
            {__a.destroy(__p);}
    template <class _Tp>
        _LIBCPP_INLINE_VISIBILITY
        static void __destroy(false_type, allocator_type&, _Tp* __p)
            {
                __p->~_Tp();
            }

    _LIBCPP_INLINE_VISIBILITY
    static size_type __max_size(true_type, const allocator_type& __a) _NOEXCEPT
            {return __a.max_size();}
    _LIBCPP_INLINE_VISIBILITY
    static size_type __max_size(false_type, const allocator_type&) _NOEXCEPT
            {return numeric_limits<size_type>::max() / sizeof(value_type);}

    _LIBCPP_INLINE_VISIBILITY
    static allocator_type
        __select_on_container_copy_construction(true_type, const allocator_type& __a)
            {return __a.select_on_container_copy_construction();}
    _LIBCPP_INLINE_VISIBILITY
    static allocator_type
        __select_on_container_copy_construction(false_type, const allocator_type& __a)
            {return __a;}
};

template <class _Traits, class _Tp>
struct __rebind_alloc_helper
{
#ifndef _LIBCPP_CXX03_LANG
    typedef typename _Traits::template rebind_alloc<_Tp>        type;
#else
    typedef typename _Traits::template rebind_alloc<_Tp>::other type;
#endif
};

// allocator

template <class _Tp>
class _LIBCPP_TEMPLATE_VIS allocator
{
public:
    typedef size_t            size_type;
    typedef ptrdiff_t         difference_type;
    typedef _Tp*              pointer;
    typedef const _Tp*        const_pointer;
    typedef _Tp&              reference;
    typedef const _Tp&        const_reference;
    typedef _Tp               value_type;

    typedef true_type propagate_on_container_move_assignment;
    typedef true_type is_always_equal;

    template <class _Up> struct rebind {typedef allocator<_Up> other;};

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    allocator() _NOEXCEPT {}

    template <class _Up>
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    allocator(const allocator<_Up>&) _NOEXCEPT {}

    _LIBCPP_INLINE_VISIBILITY pointer address(reference __x) const _NOEXCEPT
        {return _VSTD::addressof(__x);}
    _LIBCPP_INLINE_VISIBILITY const_pointer address(const_reference __x) const _NOEXCEPT
        {return _VSTD::addressof(__x);}
    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
    pointer allocate(size_type __n, allocator<void>::const_pointer = 0)
        {
        if (__n > max_size())
            __throw_length_error("allocator<T>::allocate(size_t n)"
                                 " 'n' exceeds maximum supported size");
        return static_cast<pointer>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
        }
    _LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type __n) _NOEXCEPT
        {_VSTD::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));}
    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT
        {return size_type(~0) / sizeof(_Tp);}
#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
    template <class _Up, class... _Args>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(_Up* __p, _Args&&... __args)
        {
            ::new((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
        }
#else  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p)
        {
            ::new((void*)__p) _Tp();
        }
# if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)

    template <class _A0>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0)
        {
            ::new((void*)__p) _Tp(__a0);
        }
    template <class _A0>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0)
        {
            ::new((void*)__p) _Tp(__a0);
        }
# endif  // defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0, _A1& __a1)
        {
            ::new((void*)__p) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0, _A1& __a1)
        {
            ::new((void*)__p) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0, const _A1& __a1)
        {
            ::new((void*)__p) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0, const _A1& __a1)
        {
            ::new((void*)__p) _Tp(__a0, __a1);
        }
#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
    _LIBCPP_INLINE_VISIBILITY void destroy(pointer __p) {__p->~_Tp();}
};

template <class _Tp>
class _LIBCPP_TEMPLATE_VIS allocator<const _Tp>
{
public:
    typedef size_t            size_type;
    typedef ptrdiff_t         difference_type;
    typedef const _Tp*        pointer;
    typedef const _Tp*        const_pointer;
    typedef const _Tp&        reference;
    typedef const _Tp&        const_reference;
    typedef const _Tp         value_type;

    typedef true_type propagate_on_container_move_assignment;
    typedef true_type is_always_equal;

    template <class _Up> struct rebind {typedef allocator<_Up> other;};

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    allocator() _NOEXCEPT {}

    template <class _Up>
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    allocator(const allocator<_Up>&) _NOEXCEPT {}

    _LIBCPP_INLINE_VISIBILITY const_pointer address(const_reference __x) const _NOEXCEPT
        {return _VSTD::addressof(__x);}
    _LIBCPP_INLINE_VISIBILITY pointer allocate(size_type __n, allocator<void>::const_pointer = 0)
    {
        if (__n > max_size())
            __throw_length_error("allocator<const T>::allocate(size_t n)"
                                 " 'n' exceeds maximum supported size");
        return static_cast<pointer>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
    }
    _LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type __n) _NOEXCEPT
        {_VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p), __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));}
    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT
        {return size_type(~0) / sizeof(_Tp);}
#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
    template <class _Up, class... _Args>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(_Up* __p, _Args&&... __args)
        {
            ::new((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
        }
#else  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp();
        }
# if defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)

    template <class _A0>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0);
        }
    template <class _A0>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0);
        }
# endif  // defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0, _A1& __a1)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0, _A1& __a1)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, _A0& __a0, const _A1& __a1)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
        }
    template <class _A0, class _A1>
        _LIBCPP_INLINE_VISIBILITY
        void
        construct(pointer __p, const _A0& __a0, const _A1& __a1)
        {
            ::new((void*) const_cast<_Tp *>(__p)) _Tp(__a0, __a1);
        }
#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_VARIADICS)
    _LIBCPP_INLINE_VISIBILITY void destroy(pointer __p) {__p->~_Tp();}
};

template <class _Tp, class _Up>
inline _LIBCPP_INLINE_VISIBILITY
bool operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return true;}

template <class _Tp, class _Up>
inline _LIBCPP_INLINE_VISIBILITY
bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return false;}

template <class _OutputIterator, class _Tp>
class _LIBCPP_TEMPLATE_VIS raw_storage_iterator
    : public iterator<output_iterator_tag,
                      _Tp,                                         // purposefully not C++03
                      ptrdiff_t,                                   // purposefully not C++03
                      _Tp*,                                        // purposefully not C++03
                      raw_storage_iterator<_OutputIterator, _Tp>&> // purposefully not C++03
{
private:
    _OutputIterator __x_;
public:
    _LIBCPP_INLINE_VISIBILITY explicit raw_storage_iterator(_OutputIterator __x) : __x_(__x) {}
    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator*() {return *this;}
    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(const _Tp& __element)
        {::new(_VSTD::addressof(*__x_)) _Tp(__element); return *this;}
#if _LIBCPP_STD_VER >= 14
    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(_Tp&& __element)
        {::new(_VSTD::addressof(*__x_)) _Tp(_VSTD::move(__element)); return *this;}
#endif
    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator++() {++__x_; return *this;}
    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator  operator++(int)
        {raw_storage_iterator __t(*this); ++__x_; return __t;}
#if _LIBCPP_STD_VER >= 14
    _LIBCPP_INLINE_VISIBILITY _OutputIterator base() const { return __x_; }
#endif
};

template <class _Tp>
_LIBCPP_NODISCARD_EXT _LIBCPP_NO_CFI
pair<_Tp*, ptrdiff_t>
get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT
{
    pair<_Tp*, ptrdiff_t> __r(0, 0);
    const ptrdiff_t __m = (~ptrdiff_t(0) ^
                           ptrdiff_t(ptrdiff_t(1) << (sizeof(ptrdiff_t) * __CHAR_BIT__ - 1)))
                           / sizeof(_Tp);
    if (__n > __m)
        __n = __m;
    while (__n > 0)
    {
#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
    if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
        {
            std::align_val_t __al =
                std::align_val_t(std::alignment_of<_Tp>::value);
            __r.first = static_cast<_Tp*>(::operator new(
                __n * sizeof(_Tp), __al, nothrow));
        } else {
            __r.first = static_cast<_Tp*>(::operator new(
                __n * sizeof(_Tp), nothrow));
        }
#else
    if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
        {
            // Since aligned operator new is unavailable, return an empty
            // buffer rather than one with invalid alignment.
            return __r;
        }

        __r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow));
#endif

        if (__r.first)
        {
            __r.second = __n;
            break;
        }
        __n /= 2;
    }
    return __r;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void return_temporary_buffer(_Tp* __p) _NOEXCEPT
{
  _VSTD::__libcpp_deallocate_unsized((void*)__p, _LIBCPP_ALIGNOF(_Tp));
}

#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
template <class _Tp>
struct _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr_ref
{
    _Tp* __ptr_;
};

template<class _Tp>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr
{
private:
    _Tp* __ptr_;
public:
    typedef _Tp element_type;

    _LIBCPP_INLINE_VISIBILITY explicit auto_ptr(_Tp* __p = 0) throw() : __ptr_(__p) {}
    _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr& __p) throw() : __ptr_(__p.release()) {}
    template<class _Up> _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr<_Up>& __p) throw()
        : __ptr_(__p.release()) {}
    _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr& __p) throw()
        {reset(__p.release()); return *this;}
    template<class _Up> _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr<_Up>& __p) throw()
        {reset(__p.release()); return *this;}
    _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr_ref<_Tp> __p) throw()
        {reset(__p.__ptr_); return *this;}
    _LIBCPP_INLINE_VISIBILITY ~auto_ptr() throw() {delete __ptr_;}

    _LIBCPP_INLINE_VISIBILITY _Tp& operator*() const throw()
        {return *__ptr_;}
    _LIBCPP_INLINE_VISIBILITY _Tp* operator->() const throw() {return __ptr_;}
    _LIBCPP_INLINE_VISIBILITY _Tp* get() const throw() {return __ptr_;}
    _LIBCPP_INLINE_VISIBILITY _Tp* release() throw()
    {
        _Tp* __t = __ptr_;
        __ptr_ = 0;
        return __t;
    }
    _LIBCPP_INLINE_VISIBILITY void reset(_Tp* __p = 0) throw()
    {
        if (__ptr_ != __p)
            delete __ptr_;
        __ptr_ = __p;
    }

    _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr_ref<_Tp> __p) throw() : __ptr_(__p.__ptr_) {}
    template<class _Up> _LIBCPP_INLINE_VISIBILITY operator auto_ptr_ref<_Up>() throw()
        {auto_ptr_ref<_Up> __t; __t.__ptr_ = release(); return __t;}
    template<class _Up> _LIBCPP_INLINE_VISIBILITY operator auto_ptr<_Up>() throw()
        {return auto_ptr<_Up>(release());}
};

template <>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr<void>
{
public:
    typedef void element_type;
};
#endif

template <class _Tp, int _Idx,
          bool _CanBeEmptyBase =
              is_empty<_Tp>::value && !__libcpp_is_final<_Tp>::value>
struct __compressed_pair_elem {
  typedef _Tp _ParamT;
  typedef _Tp& reference;
  typedef const _Tp& const_reference;

#ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_INLINE_VISIBILITY constexpr __compressed_pair_elem() : __value_() {}

  template <class _Up, class = typename enable_if<
      !is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
  >::type>
  _LIBCPP_INLINE_VISIBILITY
  constexpr explicit
  __compressed_pair_elem(_Up&& __u)
      : __value_(_VSTD::forward<_Up>(__u))
    {
    }

  template <class... _Args, size_t... _Indexes>
  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
  __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
                         __tuple_indices<_Indexes...>)
      : __value_(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
#else
  _LIBCPP_INLINE_VISIBILITY __compressed_pair_elem() : __value_() {}
  _LIBCPP_INLINE_VISIBILITY
  __compressed_pair_elem(_ParamT __p) : __value_(std::forward<_ParamT>(__p)) {}
#endif

  _LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return __value_; }
  _LIBCPP_INLINE_VISIBILITY
  const_reference __get() const _NOEXCEPT { return __value_; }

private:
  _Tp __value_;
};

template <class _Tp, int _Idx>
struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp {
  typedef _Tp _ParamT;
  typedef _Tp& reference;
  typedef const _Tp& const_reference;
  typedef _Tp __value_type;

#ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_INLINE_VISIBILITY constexpr __compressed_pair_elem() = default;

  template <class _Up, class = typename enable_if<
        !is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
  >::type>
  _LIBCPP_INLINE_VISIBILITY
  constexpr explicit
  __compressed_pair_elem(_Up&& __u)
      : __value_type(_VSTD::forward<_Up>(__u))
  {}

  template <class... _Args, size_t... _Indexes>
  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
  __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
                         __tuple_indices<_Indexes...>)
      : __value_type(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(_                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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