forked from boostorg/algorithm
67 lines
2.0 KiB
C++
67 lines
2.0 KiB
C++
/*
|
|
Copyright (c) Marshall Clow 2011-2012.
|
|
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
*/
|
|
|
|
/// \file partition_point.hpp
|
|
/// \brief Find the partition point in a sequence
|
|
/// \author Marshall Clow
|
|
|
|
#ifndef BOOST_ALGORITHM_PARTITION_POINT_HPP
|
|
#define BOOST_ALGORITHM_PARTITION_POINT_HPP
|
|
|
|
#include <iterator> // for std::distance, advance
|
|
|
|
#include <boost/config.hpp>
|
|
#include <boost/range/begin.hpp>
|
|
#include <boost/range/end.hpp>
|
|
|
|
namespace boost { namespace algorithm {
|
|
|
|
/// \fn partition_point ( ForwardIterator first, ForwardIterator last, Predicate p )
|
|
/// \brief Given a partitioned range, returns the partition point, i.e, the first element
|
|
/// that does not satisfy p
|
|
///
|
|
/// \param first The start of the input sequence
|
|
/// \param last One past the end of the input sequence
|
|
/// \param p The predicate to test the values with
|
|
/// \note This function is part of the C++2011 standard library.
|
|
template <typename ForwardIterator, typename Predicate>
|
|
ForwardIterator partition_point ( ForwardIterator first, ForwardIterator last, Predicate p )
|
|
{
|
|
std::size_t dist = std::distance ( first, last );
|
|
while ( first != last ) {
|
|
std::size_t d2 = dist / 2;
|
|
ForwardIterator ret_val = first;
|
|
std::advance (ret_val, d2);
|
|
if (p (*ret_val)) {
|
|
first = ++ret_val;
|
|
dist -= d2 + 1;
|
|
}
|
|
else {
|
|
last = ret_val;
|
|
dist = d2;
|
|
}
|
|
}
|
|
return first;
|
|
}
|
|
|
|
/// \fn partition_point ( Range &r, Predicate p )
|
|
/// \brief Given a partitioned range, returns the partition point
|
|
///
|
|
/// \param r The input range
|
|
/// \param p The predicate to test the values with
|
|
///
|
|
template <typename Range, typename Predicate>
|
|
typename boost::range_iterator<Range>::type partition_point ( Range &r, Predicate p )
|
|
{
|
|
return boost::algorithm::partition_point (boost::begin(r), boost::end(r), p);
|
|
}
|
|
|
|
|
|
}}
|
|
|
|
#endif // BOOST_ALGORITHM_PARTITION_POINT_HPP
|