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/// \file
// Range v3 library
//
// Copyright Eric Niebler 2014-present
//
// Use, modification and distribution is subject to 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)
//
// Project home: https://github.com/ericniebler/range-v3
//
//===-------------------------- 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 RANGES_V3_ALGORITHM_PERMUTATION_HPP
#define RANGES_V3_ALGORITHM_PERMUTATION_HPP
#include <meta/meta.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/algorithm/mismatch.hpp>
#include <range/v3/algorithm/reverse.hpp>
#include <range/v3/functional/comparisons.hpp>
#include <range/v3/functional/identity.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/iterator/concepts.hpp>
#include <range/v3/iterator/operations.hpp>
#include <range/v3/iterator/traits.hpp>
#include <range/v3/range/access.hpp>
#include <range/v3/range/concepts.hpp>
#include <range/v3/range/traits.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/utility/swap.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-algorithms
/// @{
/// \cond
namespace detail
{
template<typename I1, typename S1, typename I2, typename S2, typename C,
typename P1, typename P2>
constexpr bool is_permutation_impl(I1 begin1,
S1 end1,
I2 begin2,
S2 end2,
C pred,
P1 proj1,
P2 proj2)
{
// shorten sequences as much as possible by lopping off any equal parts
const auto mismatch =
ranges::mismatch(begin1, end1, begin2, end2, pred, proj1, proj2);
begin1 = mismatch.in1;
begin2 = mismatch.in2;
if(begin1 == end1 || begin2 == end2)
{
return begin1 == end1 && begin2 == end2;
}
// begin1 != end1 && begin2 != end2 && *begin1 != *begin2
auto l1 = distance(begin1, end1);
auto l2 = distance(begin2, end2);
if(l1 != l2)
return false;
// For each element in [f1, l1) see if there are the same number of
// equal elements in [f2, l2)
for(I1 i = begin1; i != end1; ++i)
{
// Have we already counted the number of *i in [f1, l1)?
const auto should_continue = [&] {
for(I1 j = begin1; j != i; ++j)
if(invoke(pred, invoke(proj1, *j), invoke(proj1, *i)))
return true;
return false;
}();
if(should_continue)
{
continue;
}
// Count number of *i in [f2, l2)
iter_difference_t<I2> c2 = 0;
for(I2 j = begin2; j != end2; ++j)
if(invoke(pred, invoke(proj1, *i), invoke(proj2, *j)))
++c2;
if(c2 == 0)
return false;
// Count number of *i in [i, l1) (we can start with 1)
iter_difference_t<I1> c1 = 1;
for(I1 j = next(i); j != end1; ++j)
if(invoke(pred, invoke(proj1, *i), invoke(proj1, *j)))
++c1;
if(c1 != c2)
return false;
}
return true;
}
} // namespace detail
/// \endcond
RANGES_FUNC_BEGIN(is_permutation)
/// \brief function template \c is_permutation
template(typename I1,
typename S1,
typename I2,
typename C = equal_to,
typename P1 = identity,
typename P2 = identity)(
requires forward_iterator<I1> AND sentinel_for<S1, I1> AND
forward_iterator<I2> AND indirectly_comparable<I1, I2, C, P1, P2>)
RANGES_DEPRECATED(
"Use the variant of ranges::is_permutation that takes an upper bound "
"for both sequences")
bool RANGES_FUNC(is_permutation)(I1 begin1,
S1 end1,
I2 begin2,
C pred = C{},
P1 proj1 = P1{},
P2 proj2 = P2{}) //
{
// shorten sequences as much as possible by lopping off any equal parts
for(; begin1 != end1; ++begin1, ++begin2)
if(!invoke(pred, invoke(proj1, *begin1), invoke(proj2, *begin2)))
goto not_done;
return true;
not_done:
// begin1 != end1 && *begin1 != *begin2
auto l1 = distance(begin1, end1);
if(l1 == 1)
return false;
I2 end2 = next(begin2, l1);
// For each element in [f1, l1) see if there are the same number of
// equal elements in [f2, l2)
for(I1 i = begin1; i != end1; ++i)
{
// Have we already counted the number of *i in [f1, l1)?
for(I1 j = begin1; j != i; ++j)
if(invoke(pred, invoke(proj1, *j), invoke(proj1, *i)))
goto next_iter;
{
// Count number of *i in [f2, l2)
iter_difference_t<I2> c2 = 0;
for(I2 j = begin2; j != end2; ++j)
if(invoke(pred, invoke(proj1, *i), invoke(proj2, *j)))
++c2;
if(c2 == 0)
return false;
// Count number of *i in [i, l1) (we can start with 1)
iter_difference_t<I1> c1 = 1;
for(I1 j = next(i); j != end1; ++j)
if(invoke(pred, invoke(proj1, *i), invoke(proj1, *j)))
++c1;
if(c1 != c2)
return false;
}
next_iter:;
}
return true;
}
/// \overload
template(typename I1,
typename S1,
typename I2,
typename S2,
typename C = equal_to,
typename P1 = identity,
typename P2 = identity)(
requires forward_iterator<I1> AND sentinel_for<S1, I1> AND
forward_iterator<I2> AND sentinel_for<S2, I2> AND
indirectly_comparable<I1, I2, C, P1, P2>)
constexpr bool RANGES_FUNC(is_permutation)(I1 begin1,
S1 end1,
I2 begin2,
S2 end2,
C pred = C{},
P1 proj1 = P1{},
P2 proj2 = P2{}) //
{
if(RANGES_CONSTEXPR_IF(sized_sentinel_for<S1, I1> &&
sized_sentinel_for<S2, I2>))
{
RANGES_DIAGNOSTIC_PUSH
RANGES_DIAGNOSTIC_IGNORE_DEPRECATED_DECLARATIONS
return distance(begin1, end1) == distance(begin2, end2) &&
(*this)(std::move(begin1),
std::move(end1),
std::move(begin2),
std::move(pred),
std::move(proj1),
std::move(proj2));
RANGES_DIAGNOSTIC_POP
}
return detail::is_permutation_impl(std::move(begin1),
std::move(end1),
std::move(begin2),
std::move(end2),
std::move(pred),
std::move(proj1),
std::move(proj2));
}
/// \overload
template(typename Rng1,
typename I2Ref,
typename C = equal_to,
typename P1 = identity,
typename P2 = identity)(
requires forward_range<Rng1> AND forward_iterator<uncvref_t<I2Ref>> AND
indirectly_comparable<iterator_t<Rng1>, uncvref_t<I2Ref>, C, P1, P2>)
RANGES_DEPRECATED(
"Use the variant of ranges::is_permutation that takes an upper bound "
"for both sequences")
bool RANGES_FUNC(is_permutation)(Rng1 && rng1,
I2Ref && begin2,
C pred = C{},
P1 proj1 = P1{},
P2 proj2 = P2{}) //
{
RANGES_DIAGNOSTIC_PUSH
RANGES_DIAGNOSTIC_IGNORE_DEPRECATED_DECLARATIONS
return (*this)(begin(rng1),
end(rng1),
(I2Ref &&) begin2,
std::move(pred),
std::move(proj1),
std::move(proj2));
RANGES_DIAGNOSTIC_POP
}
/// \overload
template(typename Rng1,
typename Rng2,
typename C = equal_to,
typename P1 = identity,
typename P2 = identity)(
requires forward_range<Rng1> AND forward_range<Rng2> AND
indirectly_comparable<iterator_t<Rng1>, iterator_t<Rng2>, C, P1, P2>)
constexpr bool RANGES_FUNC(is_permutation)(
Rng1 && rng1, Rng2 && rng2, C pred = C{}, P1 proj1 = P1{}, P2 proj2 = P2{}) //
{
if(RANGES_CONSTEXPR_IF(sized_range<Rng1> && sized_range<Rng2>))
{
RANGES_DIAGNOSTIC_PUSH
RANGES_DIAGNOSTIC_IGNORE_DEPRECATED_DECLARATIONS
return distance(rng1) == distance(rng2) && (*this)(begin(rng1),
end(rng1),
begin(rng2),
std::move(pred),
std::move(proj1),
std::move(proj2));
RANGES_DIAGNOSTIC_POP
}
return detail::is_permutation_impl(begin(rng1),
end(rng1),
begin(rng2),
end(rng2),
std::move(pred),
std::move(proj1),
std::move(proj2));
}
RANGES_FUNC_END(is_permutation)
RANGES_FUNC_BEGIN(next_permutation)
/// \brief function template \c next_permutation
template(typename I, typename S, typename C = less, typename P = identity)(
requires bidirectional_iterator<I> AND sentinel_for<S, I> AND
sortable<I, C, P>)
constexpr bool RANGES_FUNC(next_permutation)(I first, S end_, C pred = C{}, P proj = P{}) //
{
if(first == end_)
return false;
I last = ranges::next(first, end_), i = last;
if(first == --i)
return false;
while(true)
{
I ip1 = i;
if(invoke(pred, invoke(proj, *--i), invoke(proj, *ip1)))
{
I j = last;
while(!invoke(pred, invoke(proj, *i), invoke(proj, *--j)))
;
ranges::iter_swap(i, j);
ranges::reverse(ip1, last);
return true;
}
if(i == first)
{
ranges::reverse(first, last);
return false;
}
}
}
/// \overload
template(typename Rng, typename C = less, typename P = identity)(
requires bidirectional_range<Rng> AND sortable<iterator_t<Rng>, C, P>)
constexpr bool RANGES_FUNC(next_permutation)(Rng && rng, C pred = C{}, P proj = P{}) //
{
return (*this)(begin(rng), end(rng), std::move(pred), std::move(proj));
}
RANGES_FUNC_END(next_permutation)
RANGES_FUNC_BEGIN(prev_permutation)
/// \brief function template \c prev_permutation
template(typename I, typename S, typename C = less, typename P = identity)(
requires bidirectional_iterator<I> AND sentinel_for<S, I> AND
sortable<I, C, P>)
constexpr bool RANGES_FUNC(prev_permutation)(I first, S end_, C pred = C{}, P proj = P{}) //
{
if(first == end_)
return false;
I last = ranges::next(first, end_), i = last;
if(first == --i)
return false;
while(true)
{
I ip1 = i;
if(invoke(pred, invoke(proj, *ip1), invoke(proj, *--i)))
{
I j = last;
while(!invoke(pred, invoke(proj, *--j), invoke(proj, *i)))
;
ranges::iter_swap(i, j);
ranges::reverse(ip1, last);
return true;
}
if(i == first)
{
ranges::reverse(first, last);
return false;
}
}
}
/// \overload
template(typename Rng, typename C = less, typename P = identity)(
requires bidirectional_range<Rng> AND sortable<iterator_t<Rng>, C, P>)
constexpr bool RANGES_FUNC(prev_permutation)(Rng && rng, C pred = C{}, P proj = P{}) //
{
return (*this)(begin(rng), end(rng), std::move(pred), std::move(proj));
}
RANGES_FUNC_END(prev_permutation)
namespace cpp20
{
using ranges::is_permutation;
using ranges::next_permutation;
using ranges::prev_permutation;
} // namespace cpp20
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
|
