121 lines
3.9 KiB
C++
121 lines
3.9 KiB
C++
// -*- C++ -*-
|
|
//===-------------------------- algorithm ---------------------------------===//
|
|
//
|
|
// 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_EXPERIMENTAL_ALGORITHM
|
|
#define _LIBCPP_EXPERIMENTAL_ALGORITHM
|
|
|
|
/*
|
|
experimental/algorithm synopsis
|
|
|
|
#include <algorithm>
|
|
|
|
namespace std {
|
|
namespace experimental {
|
|
inline namespace fundamentals_v1 {
|
|
|
|
template <class ForwardIterator, class Searcher>
|
|
ForwardIterator search(ForwardIterator first, ForwardIterator last,
|
|
const Searcher &searcher);
|
|
template <class PopulationIterator, class SampleIterator, class Distance,
|
|
class UniformRandomNumberGenerator>
|
|
SampleIterator sample(PopulationIterator first, PopulationIterator last,
|
|
SampleIterator out, Distance n,
|
|
UniformRandomNumberGenerator &&g);
|
|
|
|
} // namespace fundamentals_v1
|
|
} // namespace experimental
|
|
} // namespace std
|
|
|
|
*/
|
|
|
|
#include <experimental/__config>
|
|
#include <algorithm>
|
|
#include <type_traits>
|
|
|
|
#include <__undef_min_max>
|
|
|
|
#include <__debug>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
#pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_LFTS
|
|
|
|
|
|
template <class _ForwardIterator, class _Searcher>
|
|
_LIBCPP_INLINE_VISIBILITY
|
|
_ForwardIterator search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher &__s)
|
|
{ return __s(__f, __l); }
|
|
|
|
|
|
template <class _PopulationIterator, class _SampleIterator, class _Distance,
|
|
class _UniformRandomNumberGenerator>
|
|
_LIBCPP_INLINE_VISIBILITY
|
|
_SampleIterator __sample(_PopulationIterator __first,
|
|
_PopulationIterator __last, _SampleIterator __out,
|
|
_Distance __n,
|
|
_UniformRandomNumberGenerator &&__g,
|
|
input_iterator_tag) {
|
|
|
|
_Distance __k = 0;
|
|
for (; __first != __last && __k < __n; ++__first, (void)++__k)
|
|
__out[__k] = *__first;
|
|
_Distance __sz = __k;
|
|
for (; __first != __last; ++__first, (void)++__k) {
|
|
_Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
|
|
if (__r < __sz)
|
|
__out[__r] = *__first;
|
|
}
|
|
return __out + _VSTD::min(__n, __k);
|
|
}
|
|
|
|
template <class _PopulationIterator, class _SampleIterator, class _Distance,
|
|
class _UniformRandomNumberGenerator>
|
|
_LIBCPP_INLINE_VISIBILITY
|
|
_SampleIterator __sample(_PopulationIterator __first,
|
|
_PopulationIterator __last, _SampleIterator __out,
|
|
_Distance __n,
|
|
_UniformRandomNumberGenerator &&__g,
|
|
forward_iterator_tag) {
|
|
_Distance __unsampled_sz = _VSTD::distance(__first, __last);
|
|
for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
|
|
_Distance __r =
|
|
_VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
|
|
if (__r < __n) {
|
|
*__out++ = *__first;
|
|
--__n;
|
|
}
|
|
}
|
|
return __out;
|
|
}
|
|
|
|
template <class _PopulationIterator, class _SampleIterator, class _Distance,
|
|
class _UniformRandomNumberGenerator>
|
|
_LIBCPP_INLINE_VISIBILITY
|
|
_SampleIterator sample(_PopulationIterator __first,
|
|
_PopulationIterator __last, _SampleIterator __out,
|
|
_Distance __n, _UniformRandomNumberGenerator &&__g) {
|
|
typedef typename iterator_traits<_PopulationIterator>::iterator_category
|
|
_PopCategory;
|
|
typedef typename iterator_traits<_PopulationIterator>::difference_type
|
|
_Difference;
|
|
typedef typename common_type<_Distance, _Difference>::type _CommonType;
|
|
_LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
|
|
return _VSTD_LFTS::__sample(
|
|
__first, __last, __out, _CommonType(__n),
|
|
_VSTD::forward<_UniformRandomNumberGenerator>(__g),
|
|
_PopCategory());
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_LFTS
|
|
|
|
#endif /* _LIBCPP_EXPERIMENTAL_ALGORITHM */
|