forked from OSchip/llvm-project
399 lines
14 KiB
C++
399 lines
14 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H
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#define _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H
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#include <__config>
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#include <__random/is_seed_sequence.h>
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#include <cstdint>
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#include <iosfwd>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <unsigned long long __a, unsigned long long __c,
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unsigned long long __m, unsigned long long _Mp,
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bool _MightOverflow = (__a != 0 && __m != 0 && __m-1 > (_Mp-__c)/__a),
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bool _OverflowOK = ((__m | (__m-1)) > __m), // m = 2^n
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bool _SchrageOK = (__a != 0 && __m != 0 && __m % __a <= __m / __a)> // r <= q
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struct __lce_alg_picker
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{
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static_assert(__a != 0 || __m != 0 || !_MightOverflow || _OverflowOK || _SchrageOK,
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"The current values of a, c, and m cannot generate a number "
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"within bounds of linear_congruential_engine.");
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static _LIBCPP_CONSTEXPR const bool __use_schrage = _MightOverflow &&
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!_OverflowOK &&
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_SchrageOK;
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};
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template <unsigned long long __a, unsigned long long __c,
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unsigned long long __m, unsigned long long _Mp,
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bool _UseSchrage = __lce_alg_picker<__a, __c, __m, _Mp>::__use_schrage>
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struct __lce_ta;
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// 64
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template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
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struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), true>
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{
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typedef unsigned long long result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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// Schrage's algorithm
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const result_type __q = __m / __a;
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const result_type __r = __m % __a;
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const result_type __t0 = __a * (__x % __q);
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const result_type __t1 = __r * (__x / __q);
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__x = __t0 + (__t0 < __t1) * __m - __t1;
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__x += __c - (__x >= __m - __c) * __m;
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return __x;
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}
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};
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template <unsigned long long __a, unsigned long long __m>
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struct __lce_ta<__a, 0, __m, (unsigned long long)(~0), true>
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{
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typedef unsigned long long result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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// Schrage's algorithm
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const result_type __q = __m / __a;
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const result_type __r = __m % __a;
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const result_type __t0 = __a * (__x % __q);
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const result_type __t1 = __r * (__x / __q);
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__x = __t0 + (__t0 < __t1) * __m - __t1;
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return __x;
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}
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};
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template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
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struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), false>
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{
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typedef unsigned long long result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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return (__a * __x + __c) % __m;
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}
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};
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template <unsigned long long __a, unsigned long long __c>
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struct __lce_ta<__a, __c, 0, (unsigned long long)(~0), false>
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{
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typedef unsigned long long result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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return __a * __x + __c;
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}
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};
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// 32
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template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
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struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), true>
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{
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typedef unsigned result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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const result_type __a = static_cast<result_type>(_Ap);
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const result_type __c = static_cast<result_type>(_Cp);
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const result_type __m = static_cast<result_type>(_Mp);
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// Schrage's algorithm
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const result_type __q = __m / __a;
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const result_type __r = __m % __a;
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const result_type __t0 = __a * (__x % __q);
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const result_type __t1 = __r * (__x / __q);
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__x = __t0 + (__t0 < __t1) * __m - __t1;
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__x += __c - (__x >= __m - __c) * __m;
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return __x;
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}
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};
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template <unsigned long long _Ap, unsigned long long _Mp>
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struct __lce_ta<_Ap, 0, _Mp, unsigned(~0), true>
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{
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typedef unsigned result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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const result_type __a = static_cast<result_type>(_Ap);
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const result_type __m = static_cast<result_type>(_Mp);
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// Schrage's algorithm
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const result_type __q = __m / __a;
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const result_type __r = __m % __a;
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const result_type __t0 = __a * (__x % __q);
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const result_type __t1 = __r * (__x / __q);
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__x = __t0 + (__t0 < __t1) * __m - __t1;
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return __x;
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}
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};
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template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
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struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), false>
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{
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typedef unsigned result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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const result_type __a = static_cast<result_type>(_Ap);
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const result_type __c = static_cast<result_type>(_Cp);
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const result_type __m = static_cast<result_type>(_Mp);
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return (__a * __x + __c) % __m;
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}
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};
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template <unsigned long long _Ap, unsigned long long _Cp>
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struct __lce_ta<_Ap, _Cp, 0, unsigned(~0), false>
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{
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typedef unsigned result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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const result_type __a = static_cast<result_type>(_Ap);
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const result_type __c = static_cast<result_type>(_Cp);
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return __a * __x + __c;
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}
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};
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// 16
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template <unsigned long long __a, unsigned long long __c, unsigned long long __m, bool __b>
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struct __lce_ta<__a, __c, __m, (unsigned short)(~0), __b>
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{
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typedef unsigned short result_type;
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_LIBCPP_INLINE_VISIBILITY
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static result_type next(result_type __x)
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{
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return static_cast<result_type>(__lce_ta<__a, __c, __m, unsigned(~0)>::next(__x));
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}
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};
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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class _LIBCPP_TEMPLATE_VIS linear_congruential_engine;
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template <class _CharT, class _Traits,
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class _Up, _Up _Ap, _Up _Cp, _Up _Np>
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_LIBCPP_INLINE_VISIBILITY
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basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __os,
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const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
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template <class _CharT, class _Traits,
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class _Up, _Up _Ap, _Up _Cp, _Up _Np>
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basic_istream<_CharT, _Traits>&
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operator>>(basic_istream<_CharT, _Traits>& __is,
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linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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class _LIBCPP_TEMPLATE_VIS linear_congruential_engine
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{
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public:
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// types
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typedef _UIntType result_type;
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private:
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result_type __x_;
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static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
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static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters");
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static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters");
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static_assert(is_unsigned<_UIntType>::value, "_UIntType must be unsigned type");
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public:
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static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u: 0u;
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static _LIBCPP_CONSTEXPR const result_type _Max = __m - 1u;
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static_assert(_Min < _Max, "linear_congruential_engine invalid parameters");
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// engine characteristics
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static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
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static _LIBCPP_CONSTEXPR const result_type increment = __c;
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static _LIBCPP_CONSTEXPR const result_type modulus = __m;
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_LIBCPP_INLINE_VISIBILITY
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static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
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_LIBCPP_INLINE_VISIBILITY
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static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
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static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
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// constructors and seeding functions
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#ifndef _LIBCPP_CXX03_LANG
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_LIBCPP_INLINE_VISIBILITY
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linear_congruential_engine() : linear_congruential_engine(default_seed) {}
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_LIBCPP_INLINE_VISIBILITY
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explicit linear_congruential_engine(result_type __s) { seed(__s); }
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#else
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_LIBCPP_INLINE_VISIBILITY
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explicit linear_congruential_engine(result_type __s = default_seed) {
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seed(__s);
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}
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#endif
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template<class _Sseq>
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_LIBCPP_INLINE_VISIBILITY
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explicit linear_congruential_engine(_Sseq& __q,
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typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0)
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{seed(__q);}
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_LIBCPP_INLINE_VISIBILITY
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void seed(result_type __s = default_seed)
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{seed(integral_constant<bool, __m == 0>(),
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integral_constant<bool, __c == 0>(), __s);}
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template<class _Sseq>
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_LIBCPP_INLINE_VISIBILITY
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typename enable_if
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<
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__is_seed_sequence<_Sseq, linear_congruential_engine>::value,
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void
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>::type
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seed(_Sseq& __q)
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{__seed(__q, integral_constant<unsigned,
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1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
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: (__m > 0x100000000ull))>());}
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// generating functions
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_LIBCPP_INLINE_VISIBILITY
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result_type operator()()
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{return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));}
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_LIBCPP_INLINE_VISIBILITY
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void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
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friend _LIBCPP_INLINE_VISIBILITY
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bool operator==(const linear_congruential_engine& __x,
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const linear_congruential_engine& __y)
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{return __x.__x_ == __y.__x_;}
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friend _LIBCPP_INLINE_VISIBILITY
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bool operator!=(const linear_congruential_engine& __x,
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const linear_congruential_engine& __y)
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{return !(__x == __y);}
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private:
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_LIBCPP_INLINE_VISIBILITY
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void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;}
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_LIBCPP_INLINE_VISIBILITY
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void seed(true_type, false_type, result_type __s) {__x_ = __s;}
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_LIBCPP_INLINE_VISIBILITY
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void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ?
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1 : __s % __m;}
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_LIBCPP_INLINE_VISIBILITY
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void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;}
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template<class _Sseq>
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void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
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template<class _Sseq>
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void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
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template <class _CharT, class _Traits,
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class _Up, _Up _Ap, _Up _Cp, _Up _Np>
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friend
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basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __os,
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const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
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template <class _CharT, class _Traits,
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class _Up, _Up _Ap, _Up _Cp, _Up _Np>
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friend
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basic_istream<_CharT, _Traits>&
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operator>>(basic_istream<_CharT, _Traits>& __is,
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linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
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};
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
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linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
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linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
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linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
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linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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template<class _Sseq>
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void
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linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
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integral_constant<unsigned, 1>)
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{
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const unsigned __k = 1;
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uint32_t __ar[__k+3];
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__q.generate(__ar, __ar + __k + 3);
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result_type __s = static_cast<result_type>(__ar[3] % __m);
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__x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
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}
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template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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template<class _Sseq>
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void
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linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
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integral_constant<unsigned, 2>)
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{
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const unsigned __k = 2;
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uint32_t __ar[__k+3];
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__q.generate(__ar, __ar + __k + 3);
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result_type __s = static_cast<result_type>((__ar[3] +
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((uint64_t)__ar[4] << 32)) % __m);
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__x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
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}
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template <class _CharT, class _Traits,
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class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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inline _LIBCPP_INLINE_VISIBILITY
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basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __os,
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const linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
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{
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__save_flags<_CharT, _Traits> __lx(__os);
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typedef basic_ostream<_CharT, _Traits> _Ostream;
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__os.flags(_Ostream::dec | _Ostream::left);
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__os.fill(__os.widen(' '));
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return __os << __x.__x_;
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}
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template <class _CharT, class _Traits,
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class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
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basic_istream<_CharT, _Traits>&
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operator>>(basic_istream<_CharT, _Traits>& __is,
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linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
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{
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__save_flags<_CharT, _Traits> __lx(__is);
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typedef basic_istream<_CharT, _Traits> _Istream;
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__is.flags(_Istream::dec | _Istream::skipws);
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_UIntType __t;
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__is >> __t;
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if (!__is.fail())
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__x.__x_ = __t;
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return __is;
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}
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typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
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minstd_rand0;
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typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
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minstd_rand;
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H
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