THUAI6/CAPI/cpp/grpc/include/absl/algorithm/container.h

// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: container.h
// -----------------------------------------------------------------------------
//
// This header file provides Container-based versions of algorithmic functions
// within the C++ standard library. The following standard library sets of
// functions are covered within this file:
//
//   * Algorithmic <iterator> functions
//   * Algorithmic <numeric> functions
//   * <algorithm> functions
//
// The standard library functions operate on iterator ranges; the functions
// within this API operate on containers, though many return iterator ranges.
//
// All functions within this API are named with a `c_` prefix. Calls such as
// `absl::c_xx(container, ...) are equivalent to std:: functions such as
// `std::xx(std::begin(cont), std::end(cont), ...)`. Functions that act on
// iterators but not conceptually on iterator ranges (e.g. `std::iter_swap`)
// have no equivalent here.
//
// For template parameter and variable naming, `C` indicates the container type
// to which the function is applied, `Pred` indicates the predicate object type
// to be used by the function and `T` indicates the applicable element type.

#ifndef ABSL_ALGORITHM_CONTAINER_H_
#define ABSL_ALGORITHM_CONTAINER_H_

#include <algorithm>
#include <cassert>
#include <iterator>
#include <numeric>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#include "absl/algorithm/algorithm.h"
#include "absl/base/macros.h"
#include "absl/meta/type_traits.h"

namespace absl
{
    ABSL_NAMESPACE_BEGIN
    namespace container_algorithm_internal
    {

        // NOTE: it is important to defer to ADL lookup for building with C++ modules,
        // especially for headers like <valarray> which are not visible from this file
        // but specialize std::begin and std::end.
        using std::begin;
        using std::end;

        // The type of the iterator given by begin(c) (possibly std::begin(c)).
        // ContainerIter<const vector<T>> gives vector<T>::const_iterator,
        // while ContainerIter<vector<T>> gives vector<T>::iterator.
        template<typename C>
        using ContainerIter = decltype(begin(std::declval<C&>()));

        // An MSVC bug involving template parameter substitution requires us to use
        // decltype() here instead of just std::pair.
        template<typename C1, typename C2>
        using ContainerIterPairType =
            decltype(std::make_pair(ContainerIter<C1>(), ContainerIter<C2>()));

        template<typename C>
        using ContainerDifferenceType =
            decltype(std::distance(std::declval<ContainerIter<C>>(), std::declval<ContainerIter<C>>()));

        template<typename C>
        using ContainerPointerType =
            typename std::iterator_traits<ContainerIter<C>>::pointer;

        // container_algorithm_internal::c_begin and
        // container_algorithm_internal::c_end are abbreviations for proper ADL
        // lookup of std::begin and std::end, i.e.
        //   using std::begin;
        //   using std::end;
        //   std::foo(begin(c), end(c));
        // becomes
        //   std::foo(container_algorithm_internal::begin(c),
        //            container_algorithm_internal::end(c));
        // These are meant for internal use only.

        template<typename C>
        ContainerIter<C> c_begin(C& c)
        {
            return begin(c);
        }

        template<typename C>
        ContainerIter<C> c_end(C& c)
        {
            return end(c);
        }

        template<typename T>
        struct IsUnorderedContainer : std::false_type
        {
        };

        template<class Key, class T, class Hash, class KeyEqual, class Allocator>
        struct IsUnorderedContainer<
            std::unordered_map<Key, T, Hash, KeyEqual, Allocator>> : std::true_type
        {
        };

        template<class Key, class Hash, class KeyEqual, class Allocator>
        struct IsUnorderedContainer<std::unordered_set<Key, Hash, KeyEqual, Allocator>> : std::true_type
        {
        };

        // container_algorithm_internal::c_size. It is meant for internal use only.

        template<class C>
        auto c_size(C& c) -> decltype(c.size())
        {
            return c.size();
        }

        template<class T, std::size_t N>
        constexpr std::size_t c_size(T (&)[N])
        {
            return N;
        }

    }  // namespace container_algorithm_internal

    // PUBLIC API

    //------------------------------------------------------------------------------
    // Abseil algorithm.h functions
    //------------------------------------------------------------------------------

    // c_linear_search()
    //
    // Container-based version of absl::linear_search() for performing a linear
    // search within a container.
    template<typename C, typename EqualityComparable>
    bool c_linear_search(const C& c, EqualityComparable&& value)
    {
        return linear_search(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<EqualityComparable>(value));
    }

    //------------------------------------------------------------------------------
    // <iterator> algorithms
    //------------------------------------------------------------------------------

    // c_distance()
    //
    // Container-based version of the <iterator> `std::distance()` function to
    // return the number of elements within a container.
    template<typename C>
    container_algorithm_internal::ContainerDifferenceType<const C> c_distance(
        const C& c
    )
    {
        return std::distance(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Non-modifying sequence operations
    //------------------------------------------------------------------------------

    // c_all_of()
    //
    // Container-based version of the <algorithm> `std::all_of()` function to
    // test if all elements within a container satisfy a condition.
    template<typename C, typename Pred>
    bool c_all_of(const C& c, Pred&& pred)
    {
        return std::all_of(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_any_of()
    //
    // Container-based version of the <algorithm> `std::any_of()` function to
    // test if any element in a container fulfills a condition.
    template<typename C, typename Pred>
    bool c_any_of(const C& c, Pred&& pred)
    {
        return std::any_of(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_none_of()
    //
    // Container-based version of the <algorithm> `std::none_of()` function to
    // test if no elements in a container fulfill a condition.
    template<typename C, typename Pred>
    bool c_none_of(const C& c, Pred&& pred)
    {
        return std::none_of(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_for_each()
    //
    // Container-based version of the <algorithm> `std::for_each()` function to
    // apply a function to a container's elements.
    template<typename C, typename Function>
    decay_t<Function> c_for_each(C&& c, Function&& f)
    {
        return std::for_each(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Function>(f));
    }

    // c_find()
    //
    // Container-based version of the <algorithm> `std::find()` function to find
    // the first element containing the passed value within a container value.
    template<typename C, typename T>
    container_algorithm_internal::ContainerIter<C> c_find(C& c, T&& value)
    {
        return std::find(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<T>(value));
    }

    // c_find_if()
    //
    // Container-based version of the <algorithm> `std::find_if()` function to find
    // the first element in a container matching the given condition.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerIter<C> c_find_if(C& c, Pred&& pred)
    {
        return std::find_if(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_find_if_not()
    //
    // Container-based version of the <algorithm> `std::find_if_not()` function to
    // find the first element in a container not matching the given condition.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerIter<C> c_find_if_not(C& c, Pred&& pred)
    {
        return std::find_if_not(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_find_end()
    //
    // Container-based version of the <algorithm> `std::find_end()` function to
    // find the last subsequence within a container.
    template<typename Sequence1, typename Sequence2>
    container_algorithm_internal::ContainerIter<Sequence1> c_find_end(
        Sequence1& sequence, Sequence2& subsequence
    )
    {
        return std::find_end(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(subsequence), container_algorithm_internal::c_end(subsequence));
    }

    // Overload of c_find_end() for using a predicate evaluation other than `==` as
    // the function's test condition.
    template<typename Sequence1, typename Sequence2, typename BinaryPredicate>
    container_algorithm_internal::ContainerIter<Sequence1> c_find_end(
        Sequence1& sequence, Sequence2& subsequence, BinaryPredicate&& pred
    )
    {
        return std::find_end(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(subsequence), container_algorithm_internal::c_end(subsequence), std::forward<BinaryPredicate>(pred));
    }

    // c_find_first_of()
    //
    // Container-based version of the <algorithm> `std::find_first_of()` function to
    // find the first element within the container that is also within the options
    // container.
    template<typename C1, typename C2>
    container_algorithm_internal::ContainerIter<C1> c_find_first_of(C1& container, C2& options)
    {
        return std::find_first_of(container_algorithm_internal::c_begin(container), container_algorithm_internal::c_end(container), container_algorithm_internal::c_begin(options), container_algorithm_internal::c_end(options));
    }

    // Overload of c_find_first_of() for using a predicate evaluation other than
    // `==` as the function's test condition.
    template<typename C1, typename C2, typename BinaryPredicate>
    container_algorithm_internal::ContainerIter<C1> c_find_first_of(
        C1& container, C2& options, BinaryPredicate&& pred
    )
    {
        return std::find_first_of(container_algorithm_internal::c_begin(container), container_algorithm_internal::c_end(container), container_algorithm_internal::c_begin(options), container_algorithm_internal::c_end(options), std::forward<BinaryPredicate>(pred));
    }

    // c_adjacent_find()
    //
    // Container-based version of the <algorithm> `std::adjacent_find()` function to
    // find equal adjacent elements within a container.
    template<typename Sequence>
    container_algorithm_internal::ContainerIter<Sequence> c_adjacent_find(
        Sequence& sequence
    )
    {
        return std::adjacent_find(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_adjacent_find() for using a predicate evaluation other than
    // `==` as the function's test condition.
    template<typename Sequence, typename BinaryPredicate>
    container_algorithm_internal::ContainerIter<Sequence> c_adjacent_find(
        Sequence& sequence, BinaryPredicate&& pred
    )
    {
        return std::adjacent_find(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<BinaryPredicate>(pred));
    }

    // c_count()
    //
    // Container-based version of the <algorithm> `std::count()` function to count
    // values that match within a container.
    template<typename C, typename T>
    container_algorithm_internal::ContainerDifferenceType<const C> c_count(
        const C& c, T&& value
    )
    {
        return std::count(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<T>(value));
    }

    // c_count_if()
    //
    // Container-based version of the <algorithm> `std::count_if()` function to
    // count values matching a condition within a container.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerDifferenceType<const C> c_count_if(
        const C& c, Pred&& pred
    )
    {
        return std::count_if(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_mismatch()
    //
    // Container-based version of the <algorithm> `std::mismatch()` function to
    // return the first element where two ordered containers differ. Applies `==` to
    // the first N elements of `c1` and `c2`, where N = min(size(c1), size(c2)).
    template<typename C1, typename C2>
    container_algorithm_internal::ContainerIterPairType<C1, C2>
        c_mismatch(C1& c1, C2& c2)
    {
        auto first1 = container_algorithm_internal::c_begin(c1);
        auto last1 = container_algorithm_internal::c_end(c1);
        auto first2 = container_algorithm_internal::c_begin(c2);
        auto last2 = container_algorithm_internal::c_end(c2);

        for (; first1 != last1 && first2 != last2; ++first1, (void)++first2)
        {
            // Negates equality because Cpp17EqualityComparable doesn't require clients
            // to overload both `operator==` and `operator!=`.
            if (!(*first1 == *first2))
            {
                break;
            }
        }

        return std::make_pair(first1, first2);
    }

    // Overload of c_mismatch() for using a predicate evaluation other than `==` as
    // the function's test condition. Applies `pred`to the first N elements of `c1`
    // and `c2`, where N = min(size(c1), size(c2)).
    template<typename C1, typename C2, typename BinaryPredicate>
    container_algorithm_internal::ContainerIterPairType<C1, C2>
        c_mismatch(C1& c1, C2& c2, BinaryPredicate pred)
    {
        auto first1 = container_algorithm_internal::c_begin(c1);
        auto last1 = container_algorithm_internal::c_end(c1);
        auto first2 = container_algorithm_internal::c_begin(c2);
        auto last2 = container_algorithm_internal::c_end(c2);

        for (; first1 != last1 && first2 != last2; ++first1, (void)++first2)
        {
            if (!pred(*first1, *first2))
            {
                break;
            }
        }

        return std::make_pair(first1, first2);
    }

    // c_equal()
    //
    // Container-based version of the <algorithm> `std::equal()` function to
    // test whether two containers are equal.
    //
    // NOTE: the semantics of c_equal() are slightly different than those of
    // equal(): while the latter iterates over the second container only up to the
    // size of the first container, c_equal() also checks whether the container
    // sizes are equal.  This better matches expectations about c_equal() based on
    // its signature.
    //
    // Example:
    //   vector v1 = <1, 2, 3>;
    //   vector v2 = <1, 2, 3, 4>;
    //   equal(std::begin(v1), std::end(v1), std::begin(v2)) returns true
    //   c_equal(v1, v2) returns false

    template<typename C1, typename C2>
    bool c_equal(const C1& c1, const C2& c2)
    {
        return ((container_algorithm_internal::c_size(c1) == container_algorithm_internal::c_size(c2)) && std::equal(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2)));
    }

    // Overload of c_equal() for using a predicate evaluation other than `==` as
    // the function's test condition.
    template<typename C1, typename C2, typename BinaryPredicate>
    bool c_equal(const C1& c1, const C2& c2, BinaryPredicate&& pred)
    {
        return ((container_algorithm_internal::c_size(c1) == container_algorithm_internal::c_size(c2)) && std::equal(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), std::forward<BinaryPredicate>(pred)));
    }

    // c_is_permutation()
    //
    // Container-based version of the <algorithm> `std::is_permutation()` function
    // to test whether a container is a permutation of another.
    template<typename C1, typename C2>
    bool c_is_permutation(const C1& c1, const C2& c2)
    {
        using std::begin;
        using std::end;
        return c1.size() == c2.size() &&
               std::is_permutation(begin(c1), end(c1), begin(c2));
    }

    // Overload of c_is_permutation() for using a predicate evaluation other than
    // `==` as the function's test condition.
    template<typename C1, typename C2, typename BinaryPredicate>
    bool c_is_permutation(const C1& c1, const C2& c2, BinaryPredicate&& pred)
    {
        using std::begin;
        using std::end;
        return c1.size() == c2.size() &&
               std::is_permutation(begin(c1), end(c1), begin(c2), std::forward<BinaryPredicate>(pred));
    }

    // c_search()
    //
    // Container-based version of the <algorithm> `std::search()` function to search
    // a container for a subsequence.
    template<typename Sequence1, typename Sequence2>
    container_algorithm_internal::ContainerIter<Sequence1> c_search(
        Sequence1& sequence, Sequence2& subsequence
    )
    {
        return std::search(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(subsequence), container_algorithm_internal::c_end(subsequence));
    }

    // Overload of c_search() for using a predicate evaluation other than
    // `==` as the function's test condition.
    template<typename Sequence1, typename Sequence2, typename BinaryPredicate>
    container_algorithm_internal::ContainerIter<Sequence1> c_search(
        Sequence1& sequence, Sequence2& subsequence, BinaryPredicate&& pred
    )
    {
        return std::search(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(subsequence), container_algorithm_internal::c_end(subsequence), std::forward<BinaryPredicate>(pred));
    }

    // c_search_n()
    //
    // Container-based version of the <algorithm> `std::search_n()` function to
    // search a container for the first sequence of N elements.
    template<typename Sequence, typename Size, typename T>
    container_algorithm_internal::ContainerIter<Sequence> c_search_n(
        Sequence& sequence, Size count, T&& value
    )
    {
        return std::search_n(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), count, std::forward<T>(value));
    }

    // Overload of c_search_n() for using a predicate evaluation other than
    // `==` as the function's test condition.
    template<typename Sequence, typename Size, typename T, typename BinaryPredicate>
    container_algorithm_internal::ContainerIter<Sequence> c_search_n(
        Sequence& sequence, Size count, T&& value, BinaryPredicate&& pred
    )
    {
        return std::search_n(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), count, std::forward<T>(value), std::forward<BinaryPredicate>(pred));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Modifying sequence operations
    //------------------------------------------------------------------------------

    // c_copy()
    //
    // Container-based version of the <algorithm> `std::copy()` function to copy a
    // container's elements into an iterator.
    template<typename InputSequence, typename OutputIterator>
    OutputIterator c_copy(const InputSequence& input, OutputIterator output)
    {
        return std::copy(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output);
    }

    // c_copy_n()
    //
    // Container-based version of the <algorithm> `std::copy_n()` function to copy a
    // container's first N elements into an iterator.
    template<typename C, typename Size, typename OutputIterator>
    OutputIterator c_copy_n(const C& input, Size n, OutputIterator output)
    {
        return std::copy_n(container_algorithm_internal::c_begin(input), n, output);
    }

    // c_copy_if()
    //
    // Container-based version of the <algorithm> `std::copy_if()` function to copy
    // a container's elements satisfying some condition into an iterator.
    template<typename InputSequence, typename OutputIterator, typename Pred>
    OutputIterator c_copy_if(const InputSequence& input, OutputIterator output, Pred&& pred)
    {
        return std::copy_if(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output, std::forward<Pred>(pred));
    }

    // c_copy_backward()
    //
    // Container-based version of the <algorithm> `std::copy_backward()` function to
    // copy a container's elements in reverse order into an iterator.
    template<typename C, typename BidirectionalIterator>
    BidirectionalIterator c_copy_backward(const C& src, BidirectionalIterator dest)
    {
        return std::copy_backward(container_algorithm_internal::c_begin(src), container_algorithm_internal::c_end(src), dest);
    }

    // c_move()
    //
    // Container-based version of the <algorithm> `std::move()` function to move
    // a container's elements into an iterator.
    template<typename C, typename OutputIterator>
    OutputIterator c_move(C&& src, OutputIterator dest)
    {
        return std::move(container_algorithm_internal::c_begin(src), container_algorithm_internal::c_end(src), dest);
    }

    // c_move_backward()
    //
    // Container-based version of the <algorithm> `std::move_backward()` function to
    // move a container's elements into an iterator in reverse order.
    template<typename C, typename BidirectionalIterator>
    BidirectionalIterator c_move_backward(C&& src, BidirectionalIterator dest)
    {
        return std::move_backward(container_algorithm_internal::c_begin(src), container_algorithm_internal::c_end(src), dest);
    }

    // c_swap_ranges()
    //
    // Container-based version of the <algorithm> `std::swap_ranges()` function to
    // swap a container's elements with another container's elements. Swaps the
    // first N elements of `c1` and `c2`, where N = min(size(c1), size(c2)).
    template<typename C1, typename C2>
    container_algorithm_internal::ContainerIter<C2> c_swap_ranges(C1& c1, C2& c2)
    {
        auto first1 = container_algorithm_internal::c_begin(c1);
        auto last1 = container_algorithm_internal::c_end(c1);
        auto first2 = container_algorithm_internal::c_begin(c2);
        auto last2 = container_algorithm_internal::c_end(c2);

        using std::swap;
        for (; first1 != last1 && first2 != last2; ++first1, (void)++first2)
        {
            swap(*first1, *first2);
        }
        return first2;
    }

    // c_transform()
    //
    // Container-based version of the <algorithm> `std::transform()` function to
    // transform a container's elements using the unary operation, storing the
    // result in an iterator pointing to the last transformed element in the output
    // range.
    template<typename InputSequence, typename OutputIterator, typename UnaryOp>
    OutputIterator c_transform(const InputSequence& input, OutputIterator output, UnaryOp&& unary_op)
    {
        return std::transform(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output, std::forward<UnaryOp>(unary_op));
    }

    // Overload of c_transform() for performing a transformation using a binary
    // predicate. Applies `binary_op` to the first N elements of `c1` and `c2`,
    // where N = min(size(c1), size(c2)).
    template<typename InputSequence1, typename InputSequence2, typename OutputIterator, typename BinaryOp>
    OutputIterator c_transform(const InputSequence1& input1, const InputSequence2& input2, OutputIterator output, BinaryOp&& binary_op)
    {
        auto first1 = container_algorithm_internal::c_begin(input1);
        auto last1 = container_algorithm_internal::c_end(input1);
        auto first2 = container_algorithm_internal::c_begin(input2);
        auto last2 = container_algorithm_internal::c_end(input2);
        for (; first1 != last1 && first2 != last2;
             ++first1, (void)++first2, ++output)
        {
            *output = binary_op(*first1, *first2);
        }

        return output;
    }

    // c_replace()
    //
    // Container-based version of the <algorithm> `std::replace()` function to
    // replace a container's elements of some value with a new value. The container
    // is modified in place.
    template<typename Sequence, typename T>
    void c_replace(Sequence& sequence, const T& old_value, const T& new_value)
    {
        std::replace(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), old_value, new_value);
    }

    // c_replace_if()
    //
    // Container-based version of the <algorithm> `std::replace_if()` function to
    // replace a container's elements of some value with a new value based on some
    // condition. The container is modified in place.
    template<typename C, typename Pred, typename T>
    void c_replace_if(C& c, Pred&& pred, T&& new_value)
    {
        std::replace_if(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred), std::forward<T>(new_value));
    }

    // c_replace_copy()
    //
    // Container-based version of the <algorithm> `std::replace_copy()` function to
    // replace a container's elements of some value with a new value  and return the
    // results within an iterator.
    template<typename C, typename OutputIterator, typename T>
    OutputIterator c_replace_copy(const C& c, OutputIterator result, T&& old_value, T&& new_value)
    {
        return std::replace_copy(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result, std::forward<T>(old_value), std::forward<T>(new_value));
    }

    // c_replace_copy_if()
    //
    // Container-based version of the <algorithm> `std::replace_copy_if()` function
    // to replace a container's elements of some value with a new value based on
    // some condition, and return the results within an iterator.
    template<typename C, typename OutputIterator, typename Pred, typename T>
    OutputIterator c_replace_copy_if(const C& c, OutputIterator result, Pred&& pred, T&& new_value)
    {
        return std::replace_copy_if(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result, std::forward<Pred>(pred), std::forward<T>(new_value));
    }

    // c_fill()
    //
    // Container-based version of the <algorithm> `std::fill()` function to fill a
    // container with some value.
    template<typename C, typename T>
    void c_fill(C& c, T&& value)
    {
        std::fill(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<T>(value));
    }

    // c_fill_n()
    //
    // Container-based version of the <algorithm> `std::fill_n()` function to fill
    // the first N elements in a container with some value.
    template<typename C, typename Size, typename T>
    void c_fill_n(C& c, Size n, T&& value)
    {
        std::fill_n(container_algorithm_internal::c_begin(c), n, std::forward<T>(value));
    }

    // c_generate()
    //
    // Container-based version of the <algorithm> `std::generate()` function to
    // assign a container's elements to the values provided by the given generator.
    template<typename C, typename Generator>
    void c_generate(C& c, Generator&& gen)
    {
        std::generate(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Generator>(gen));
    }

    // c_generate_n()
    //
    // Container-based version of the <algorithm> `std::generate_n()` function to
    // assign a container's first N elements to the values provided by the given
    // generator.
    template<typename C, typename Size, typename Generator>
    container_algorithm_internal::ContainerIter<C> c_generate_n(C& c, Size n, Generator&& gen)
    {
        return std::generate_n(container_algorithm_internal::c_begin(c), n, std::forward<Generator>(gen));
    }

    // Note: `c_xx()` <algorithm> container versions for `remove()`, `remove_if()`,
    // and `unique()` are omitted, because it's not clear whether or not such
    // functions should call erase on their supplied sequences afterwards. Either
    // behavior would be surprising for a different set of users.

    // c_remove_copy()
    //
    // Container-based version of the <algorithm> `std::remove_copy()` function to
    // copy a container's elements while removing any elements matching the given
    // `value`.
    template<typename C, typename OutputIterator, typename T>
    OutputIterator c_remove_copy(const C& c, OutputIterator result, T&& value)
    {
        return std::remove_copy(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result, std::forward<T>(value));
    }

    // c_remove_copy_if()
    //
    // Container-based version of the <algorithm> `std::remove_copy_if()` function
    // to copy a container's elements while removing any elements matching the given
    // condition.
    template<typename C, typename OutputIterator, typename Pred>
    OutputIterator c_remove_copy_if(const C& c, OutputIterator result, Pred&& pred)
    {
        return std::remove_copy_if(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result, std::forward<Pred>(pred));
    }

    // c_unique_copy()
    //
    // Container-based version of the <algorithm> `std::unique_copy()` function to
    // copy a container's elements while removing any elements containing duplicate
    // values.
    template<typename C, typename OutputIterator>
    OutputIterator c_unique_copy(const C& c, OutputIterator result)
    {
        return std::unique_copy(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result);
    }

    // Overload of c_unique_copy() for using a predicate evaluation other than
    // `==` for comparing uniqueness of the element values.
    template<typename C, typename OutputIterator, typename BinaryPredicate>
    OutputIterator c_unique_copy(const C& c, OutputIterator result, BinaryPredicate&& pred)
    {
        return std::unique_copy(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), result, std::forward<BinaryPredicate>(pred));
    }

    // c_reverse()
    //
    // Container-based version of the <algorithm> `std::reverse()` function to
    // reverse a container's elements.
    template<typename Sequence>
    void c_reverse(Sequence& sequence)
    {
        std::reverse(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // c_reverse_copy()
    //
    // Container-based version of the <algorithm> `std::reverse()` function to
    // reverse a container's elements and write them to an iterator range.
    template<typename C, typename OutputIterator>
    OutputIterator c_reverse_copy(const C& sequence, OutputIterator result)
    {
        return std::reverse_copy(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), result);
    }

    // c_rotate()
    //
    // Container-based version of the <algorithm> `std::rotate()` function to
    // shift a container's elements leftward such that the `middle` element becomes
    // the first element in the container.
    template<typename C, typename Iterator = container_algorithm_internal::ContainerIter<C>>
    Iterator c_rotate(C& sequence, Iterator middle)
    {
        return absl::rotate(container_algorithm_internal::c_begin(sequence), middle, container_algorithm_internal::c_end(sequence));
    }

    // c_rotate_copy()
    //
    // Container-based version of the <algorithm> `std::rotate_copy()` function to
    // shift a container's elements leftward such that the `middle` element becomes
    // the first element in a new iterator range.
    template<typename C, typename OutputIterator>
    OutputIterator c_rotate_copy(
        const C& sequence,
        container_algorithm_internal::ContainerIter<const C> middle,
        OutputIterator result
    )
    {
        return std::rotate_copy(container_algorithm_internal::c_begin(sequence), middle, container_algorithm_internal::c_end(sequence), result);
    }

    // c_shuffle()
    //
    // Container-based version of the <algorithm> `std::shuffle()` function to
    // randomly shuffle elements within the container using a `gen()` uniform random
    // number generator.
    template<typename RandomAccessContainer, typename UniformRandomBitGenerator>
    void c_shuffle(RandomAccessContainer& c, UniformRandomBitGenerator&& gen)
    {
        std::shuffle(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<UniformRandomBitGenerator>(gen));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Partition functions
    //------------------------------------------------------------------------------

    // c_is_partitioned()
    //
    // Container-based version of the <algorithm> `std::is_partitioned()` function
    // to test whether all elements in the container for which `pred` returns `true`
    // precede those for which `pred` is `false`.
    template<typename C, typename Pred>
    bool c_is_partitioned(const C& c, Pred&& pred)
    {
        return std::is_partitioned(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_partition()
    //
    // Container-based version of the <algorithm> `std::partition()` function
    // to rearrange all elements in a container in such a way that all elements for
    // which `pred` returns `true` precede all those for which it returns `false`,
    // returning an iterator to the first element of the second group.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerIter<C> c_partition(C& c, Pred&& pred)
    {
        return std::partition(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_stable_partition()
    //
    // Container-based version of the <algorithm> `std::stable_partition()` function
    // to rearrange all elements in a container in such a way that all elements for
    // which `pred` returns `true` precede all those for which it returns `false`,
    // preserving the relative ordering between the two groups. The function returns
    // an iterator to the first element of the second group.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerIter<C> c_stable_partition(C& c, Pred&& pred)
    {
        return std::stable_partition(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    // c_partition_copy()
    //
    // Container-based version of the <algorithm> `std::partition_copy()` function
    // to partition a container's elements and return them into two iterators: one
    // for which `pred` returns `true`, and one for which `pred` returns `false.`

    template<typename C, typename OutputIterator1, typename OutputIterator2, typename Pred>
    std::pair<OutputIterator1, OutputIterator2> c_partition_copy(
        const C& c, OutputIterator1 out_true, OutputIterator2 out_false, Pred&& pred
    )
    {
        return std::partition_copy(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), out_true, out_false, std::forward<Pred>(pred));
    }

    // c_partition_point()
    //
    // Container-based version of the <algorithm> `std::partition_point()` function
    // to return the first element of an already partitioned container for which
    // the given `pred` is not `true`.
    template<typename C, typename Pred>
    container_algorithm_internal::ContainerIter<C> c_partition_point(C& c, Pred&& pred)
    {
        return std::partition_point(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<Pred>(pred));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Sorting functions
    //------------------------------------------------------------------------------

    // c_sort()
    //
    // Container-based version of the <algorithm> `std::sort()` function
    // to sort elements in ascending order of their values.
    template<typename C>
    void c_sort(C& c)
    {
        std::sort(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_sort() for performing a `comp` comparison other than the
    // default `operator<`.
    template<typename C, typename LessThan>
    void c_sort(C& c, LessThan&& comp)
    {
        std::sort(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_stable_sort()
    //
    // Container-based version of the <algorithm> `std::stable_sort()` function
    // to sort elements in ascending order of their values, preserving the order
    // of equivalents.
    template<typename C>
    void c_stable_sort(C& c)
    {
        std::stable_sort(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_stable_sort() for performing a `comp` comparison other than the
    // default `operator<`.
    template<typename C, typename LessThan>
    void c_stable_sort(C& c, LessThan&& comp)
    {
        std::stable_sort(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_is_sorted()
    //
    // Container-based version of the <algorithm> `std::is_sorted()` function
    // to evaluate whether the given container is sorted in ascending order.
    template<typename C>
    bool c_is_sorted(const C& c)
    {
        return std::is_sorted(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // c_is_sorted() overload for performing a `comp` comparison other than the
    // default `operator<`.
    template<typename C, typename LessThan>
    bool c_is_sorted(const C& c, LessThan&& comp)
    {
        return std::is_sorted(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_partial_sort()
    //
    // Container-based version of the <algorithm> `std::partial_sort()` function
    // to rearrange elements within a container such that elements before `middle`
    // are sorted in ascending order.
    template<typename RandomAccessContainer>
    void c_partial_sort(
        RandomAccessContainer& sequence,
        container_algorithm_internal::ContainerIter<RandomAccessContainer> middle
    )
    {
        std::partial_sort(container_algorithm_internal::c_begin(sequence), middle, container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_partial_sort() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename RandomAccessContainer, typename LessThan>
    void c_partial_sort(
        RandomAccessContainer& sequence,
        container_algorithm_internal::ContainerIter<RandomAccessContainer> middle,
        LessThan&& comp
    )
    {
        std::partial_sort(container_algorithm_internal::c_begin(sequence), middle, container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_partial_sort_copy()
    //
    // Container-based version of the <algorithm> `std::partial_sort_copy()`
    // function to sort the elements in the given range `result` within the larger
    // `sequence` in ascending order (and using `result` as the output parameter).
    // At most min(result.last - result.first, sequence.last - sequence.first)
    // elements from the sequence will be stored in the result.
    template<typename C, typename RandomAccessContainer>
    container_algorithm_internal::ContainerIter<RandomAccessContainer>
        c_partial_sort_copy(const C& sequence, RandomAccessContainer& result)
    {
        return std::partial_sort_copy(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(result), container_algorithm_internal::c_end(result));
    }

    // Overload of c_partial_sort_copy() for performing a `comp` comparison other
    // than the default `operator<`.
    template<typename C, typename RandomAccessContainer, typename LessThan>
    container_algorithm_internal::ContainerIter<RandomAccessContainer>
        c_partial_sort_copy(const C& sequence, RandomAccessContainer& result, LessThan&& comp)
    {
        return std::partial_sort_copy(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), container_algorithm_internal::c_begin(result), container_algorithm_internal::c_end(result), std::forward<LessThan>(comp));
    }

    // c_is_sorted_until()
    //
    // Container-based version of the <algorithm> `std::is_sorted_until()` function
    // to return the first element within a container that is not sorted in
    // ascending order as an iterator.
    template<typename C>
    container_algorithm_internal::ContainerIter<C> c_is_sorted_until(C& c)
    {
        return std::is_sorted_until(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_is_sorted_until() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename C, typename LessThan>
    container_algorithm_internal::ContainerIter<C> c_is_sorted_until(
        C& c, LessThan&& comp
    )
    {
        return std::is_sorted_until(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_nth_element()
    //
    // Container-based version of the <algorithm> `std::nth_element()` function
    // to rearrange the elements within a container such that the `nth` element
    // would be in that position in an ordered sequence; other elements may be in
    // any order, except that all preceding `nth` will be less than that element,
    // and all following `nth` will be greater than that element.
    template<typename RandomAccessContainer>
    void c_nth_element(
        RandomAccessContainer& sequence,
        container_algorithm_internal::ContainerIter<RandomAccessContainer> nth
    )
    {
        std::nth_element(container_algorithm_internal::c_begin(sequence), nth, container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_nth_element() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename RandomAccessContainer, typename LessThan>
    void c_nth_element(
        RandomAccessContainer& sequence,
        container_algorithm_internal::ContainerIter<RandomAccessContainer> nth,
        LessThan&& comp
    )
    {
        std::nth_element(container_algorithm_internal::c_begin(sequence), nth, container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Binary Search
    //------------------------------------------------------------------------------

    // c_lower_bound()
    //
    // Container-based version of the <algorithm> `std::lower_bound()` function
    // to return an iterator pointing to the first element in a sorted container
    // which does not compare less than `value`.
    template<typename Sequence, typename T>
    container_algorithm_internal::ContainerIter<Sequence> c_lower_bound(
        Sequence& sequence, T&& value
    )
    {
        return std::lower_bound(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value));
    }

    // Overload of c_lower_bound() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename Sequence, typename T, typename LessThan>
    container_algorithm_internal::ContainerIter<Sequence> c_lower_bound(
        Sequence& sequence, T&& value, LessThan&& comp
    )
    {
        return std::lower_bound(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value), std::forward<LessThan>(comp));
    }

    // c_upper_bound()
    //
    // Container-based version of the <algorithm> `std::upper_bound()` function
    // to return an iterator pointing to the first element in a sorted container
    // which is greater than `value`.
    template<typename Sequence, typename T>
    container_algorithm_internal::ContainerIter<Sequence> c_upper_bound(
        Sequence& sequence, T&& value
    )
    {
        return std::upper_bound(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value));
    }

    // Overload of c_upper_bound() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename Sequence, typename T, typename LessThan>
    container_algorithm_internal::ContainerIter<Sequence> c_upper_bound(
        Sequence& sequence, T&& value, LessThan&& comp
    )
    {
        return std::upper_bound(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value), std::forward<LessThan>(comp));
    }

    // c_equal_range()
    //
    // Container-based version of the <algorithm> `std::equal_range()` function
    // to return an iterator pair pointing to the first and last elements in a
    // sorted container which compare equal to `value`.
    template<typename Sequence, typename T>
    container_algorithm_internal::ContainerIterPairType<Sequence, Sequence>
        c_equal_range(Sequence& sequence, T&& value)
    {
        return std::equal_range(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value));
    }

    // Overload of c_equal_range() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename Sequence, typename T, typename LessThan>
    container_algorithm_internal::ContainerIterPairType<Sequence, Sequence>
        c_equal_range(Sequence& sequence, T&& value, LessThan&& comp)
    {
        return std::equal_range(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value), std::forward<LessThan>(comp));
    }

    // c_binary_search()
    //
    // Container-based version of the <algorithm> `std::binary_search()` function
    // to test if any element in the sorted container contains a value equivalent to
    // 'value'.
    template<typename Sequence, typename T>
    bool c_binary_search(Sequence&& sequence, T&& value)
    {
        return std::binary_search(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value));
    }

    // Overload of c_binary_search() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename Sequence, typename T, typename LessThan>
    bool c_binary_search(Sequence&& sequence, T&& value, LessThan&& comp)
    {
        return std::binary_search(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value), std::forward<LessThan>(comp));
    }

    //------------------------------------------------------------------------------
    // <algorithm> Merge functions
    //------------------------------------------------------------------------------

    // c_merge()
    //
    // Container-based version of the <algorithm> `std::merge()` function
    // to merge two sorted containers into a single sorted iterator.
    template<typename C1, typename C2, typename OutputIterator>
    OutputIterator c_merge(const C1& c1, const C2& c2, OutputIterator result)
    {
        return std::merge(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), result);
    }

    // Overload of c_merge() for performing a `comp` comparison other than
    // the default `operator<`.
    template<typename C1, typename C2, typename OutputIterator, typename LessThan>
    OutputIterator c_merge(const C1& c1, const C2& c2, OutputIterator result, LessThan&& comp)
    {
        return std::merge(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), result, std::forward<LessThan>(comp));
    }

    // c_inplace_merge()
    //
    // Container-based version of the <algorithm> `std::inplace_merge()` function
    // to merge a supplied iterator `middle` into a container.
    template<typename C>
    void c_inplace_merge(C& c, container_algorithm_internal::ContainerIter<C> middle)
    {
        std::inplace_merge(container_algorithm_internal::c_begin(c), middle, container_algorithm_internal::c_end(c));
    }

    // Overload of c_inplace_merge() for performing a merge using a `comp` other
    // than `operator<`.
    template<typename C, typename LessThan>
    void c_inplace_merge(C& c, container_algorithm_internal::ContainerIter<C> middle, LessThan&& comp)
    {
        std::inplace_merge(container_algorithm_internal::c_begin(c), middle, container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_includes()
    //
    // Container-based version of the <algorithm> `std::includes()` function
    // to test whether a sorted container `c1` entirely contains another sorted
    // container `c2`.
    template<typename C1, typename C2>
    bool c_includes(const C1& c1, const C2& c2)
    {
        return std::includes(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2));
    }

    // Overload of c_includes() for performing a merge using a `comp` other than
    // `operator<`.
    template<typename C1, typename C2, typename LessThan>
    bool c_includes(const C1& c1, const C2& c2, LessThan&& comp)
    {
        return std::includes(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), std::forward<LessThan>(comp));
    }

    // c_set_union()
    //
    // Container-based version of the <algorithm> `std::set_union()` function
    // to return an iterator containing the union of two containers; duplicate
    // values are not copied into the output.
    template<typename C1, typename C2, typename OutputIterator, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_union(const C1& c1, const C2& c2, OutputIterator output)
    {
        return std::set_union(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output);
    }

    // Overload of c_set_union() for performing a merge using a `comp` other than
    // `operator<`.
    template<typename C1, typename C2, typename OutputIterator, typename LessThan, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_union(const C1& c1, const C2& c2, OutputIterator output, LessThan&& comp)
    {
        return std::set_union(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output, std::forward<LessThan>(comp));
    }

    // c_set_intersection()
    //
    // Container-based version of the <algorithm> `std::set_intersection()` function
    // to return an iterator containing the intersection of two sorted containers.
    template<typename C1, typename C2, typename OutputIterator, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_intersection(const C1& c1, const C2& c2, OutputIterator output)
    {
        // In debug builds, ensure that both containers are sorted with respect to the
        // default comparator. std::set_intersection requires the containers be sorted
        // using operator<.
        assert(absl::c_is_sorted(c1));
        assert(absl::c_is_sorted(c2));
        return std::set_intersection(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output);
    }

    // Overload of c_set_intersection() for performing a merge using a `comp` other
    // than `operator<`.
    template<typename C1, typename C2, typename OutputIterator, typename LessThan, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_intersection(const C1& c1, const C2& c2, OutputIterator output, LessThan&& comp)
    {
        // In debug builds, ensure that both containers are sorted with respect to the
        // default comparator. std::set_intersection requires the containers be sorted
        // using the same comparator.
        assert(absl::c_is_sorted(c1, comp));
        assert(absl::c_is_sorted(c2, comp));
        return std::set_intersection(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output, std::forward<LessThan>(comp));
    }

    // c_set_difference()
    //
    // Container-based version of the <algorithm> `std::set_difference()` function
    // to return an iterator containing elements present in the first container but
    // not in the second.
    template<typename C1, typename C2, typename OutputIterator, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_difference(const C1& c1, const C2& c2, OutputIterator output)
    {
        return std::set_difference(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output);
    }

    // Overload of c_set_difference() for performing a merge using a `comp` other
    // than `operator<`.
    template<typename C1, typename C2, typename OutputIterator, typename LessThan, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_difference(const C1& c1, const C2& c2, OutputIterator output, LessThan&& comp)
    {
        return std::set_difference(container_algorithm_internal::c_begin(c1), container_algorithm_internal::c_end(c1), container_algorithm_internal::c_begin(c2), container_algorithm_internal::c_end(c2), output, std::forward<LessThan>(comp));
    }

    // c_set_symmetric_difference()
    //
    // Container-based version of the <algorithm> `std::set_symmetric_difference()`
    // function to return an iterator containing elements present in either one
    // container or the other, but not both.
    template<typename C1, typename C2, typename OutputIterator, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_symmetric_difference(const C1& c1, const C2& c2, OutputIterator output)
    {
        return std::set_symmetric_difference(
            container_algorithm_internal::c_begin(c1),
            container_algorithm_internal::c_end(c1),
            container_algorithm_internal::c_begin(c2),
            container_algorithm_internal::c_end(c2),
            output
        );
    }

    // Overload of c_set_symmetric_difference() for performing a merge using a
    // `comp` other than `operator<`.
    template<typename C1, typename C2, typename OutputIterator, typename LessThan, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C1>::value, void>::type, typename = typename std::enable_if<!container_algorithm_internal::IsUnorderedContainer<C2>::value, void>::type>
    OutputIterator c_set_symmetric_difference(const C1& c1, const C2& c2, OutputIterator output, LessThan&& comp)
    {
        return std::set_symmetric_difference(
            container_algorithm_internal::c_begin(c1),
            container_algorithm_internal::c_end(c1),
            container_algorithm_internal::c_begin(c2),
            container_algorithm_internal::c_end(c2),
            output,
            std::forward<LessThan>(comp)
        );
    }

    //------------------------------------------------------------------------------
    // <algorithm> Heap functions
    //------------------------------------------------------------------------------

    // c_push_heap()
    //
    // Container-based version of the <algorithm> `std::push_heap()` function
    // to push a value onto a container heap.
    template<typename RandomAccessContainer>
    void c_push_heap(RandomAccessContainer& sequence)
    {
        std::push_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_push_heap() for performing a push operation on a heap using a
    // `comp` other than `operator<`.
    template<typename RandomAccessContainer, typename LessThan>
    void c_push_heap(RandomAccessContainer& sequence, LessThan&& comp)
    {
        std::push_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_pop_heap()
    //
    // Container-based version of the <algorithm> `std::pop_heap()` function
    // to pop a value from a heap container.
    template<typename RandomAccessContainer>
    void c_pop_heap(RandomAccessContainer& sequence)
    {
        std::pop_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_pop_heap() for performing a pop operation on a heap using a
    // `comp` other than `operator<`.
    template<typename RandomAccessContainer, typename LessThan>
    void c_pop_heap(RandomAccessContainer& sequence, LessThan&& comp)
    {
        std::pop_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_make_heap()
    //
    // Container-based version of the <algorithm> `std::make_heap()` function
    // to make a container a heap.
    template<typename RandomAccessContainer>
    void c_make_heap(RandomAccessContainer& sequence)
    {
        std::make_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_make_heap() for performing heap comparisons using a
    // `comp` other than `operator<`
    template<typename RandomAccessContainer, typename LessThan>
    void c_make_heap(RandomAccessContainer& sequence, LessThan&& comp)
    {
        std::make_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_sort_heap()
    //
    // Container-based version of the <algorithm> `std::sort_heap()` function
    // to sort a heap into ascending order (after which it is no longer a heap).
    template<typename RandomAccessContainer>
    void c_sort_heap(RandomAccessContainer& sequence)
    {
        std::sort_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_sort_heap() for performing heap comparisons using a
    // `comp` other than `operator<`
    template<typename RandomAccessContainer, typename LessThan>
    void c_sort_heap(RandomAccessContainer& sequence, LessThan&& comp)
    {
        std::sort_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_is_heap()
    //
    // Container-based version of the <algorithm> `std::is_heap()` function
    // to check whether the given container is a heap.
    template<typename RandomAccessContainer>
    bool c_is_heap(const RandomAccessContainer& sequence)
    {
        return std::is_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_is_heap() for performing heap comparisons using a
    // `comp` other than `operator<`
    template<typename RandomAccessContainer, typename LessThan>
    bool c_is_heap(const RandomAccessContainer& sequence, LessThan&& comp)
    {
        return std::is_heap(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_is_heap_until()
    //
    // Container-based version of the <algorithm> `std::is_heap_until()` function
    // to find the first element in a given container which is not in heap order.
    template<typename RandomAccessContainer>
    container_algorithm_internal::ContainerIter<RandomAccessContainer>
        c_is_heap_until(RandomAccessContainer& sequence)
    {
        return std::is_heap_until(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_is_heap_until() for performing heap comparisons using a
    // `comp` other than `operator<`
    template<typename RandomAccessContainer, typename LessThan>
    container_algorithm_internal::ContainerIter<RandomAccessContainer>
        c_is_heap_until(RandomAccessContainer& sequence, LessThan&& comp)
    {
        return std::is_heap_until(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    //------------------------------------------------------------------------------
    //  <algorithm> Min/max
    //------------------------------------------------------------------------------

    // c_min_element()
    //
    // Container-based version of the <algorithm> `std::min_element()` function
    // to return an iterator pointing to the element with the smallest value, using
    // `operator<` to make the comparisons.
    template<typename Sequence>
    container_algorithm_internal::ContainerIter<Sequence> c_min_element(
        Sequence& sequence
    )
    {
        return std::min_element(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_min_element() for performing a `comp` comparison other than
    // `operator<`.
    template<typename Sequence, typename LessThan>
    container_algorithm_internal::ContainerIter<Sequence> c_min_element(
        Sequence& sequence, LessThan&& comp
    )
    {
        return std::min_element(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_max_element()
    //
    // Container-based version of the <algorithm> `std::max_element()` function
    // to return an iterator pointing to the element with the largest value, using
    // `operator<` to make the comparisons.
    template<typename Sequence>
    container_algorithm_internal::ContainerIter<Sequence> c_max_element(
        Sequence& sequence
    )
    {
        return std::max_element(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence));
    }

    // Overload of c_max_element() for performing a `comp` comparison other than
    // `operator<`.
    template<typename Sequence, typename LessThan>
    container_algorithm_internal::ContainerIter<Sequence> c_max_element(
        Sequence& sequence, LessThan&& comp
    )
    {
        return std::max_element(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<LessThan>(comp));
    }

    // c_minmax_element()
    //
    // Container-based version of the <algorithm> `std::minmax_element()` function
    // to return a pair of iterators pointing to the elements containing the
    // smallest and largest values, respectively, using `operator<` to make the
    // comparisons.
    template<typename C>
    container_algorithm_internal::ContainerIterPairType<C, C>
        c_minmax_element(C& c)
    {
        return std::minmax_element(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_minmax_element() for performing `comp` comparisons other than
    // `operator<`.
    template<typename C, typename LessThan>
    container_algorithm_internal::ContainerIterPairType<C, C>
        c_minmax_element(C& c, LessThan&& comp)
    {
        return std::minmax_element(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    //------------------------------------------------------------------------------
    //  <algorithm> Lexicographical Comparisons
    //------------------------------------------------------------------------------

    // c_lexicographical_compare()
    //
    // Container-based version of the <algorithm> `std::lexicographical_compare()`
    // function to lexicographically compare (e.g. sort words alphabetically) two
    // container sequences. The comparison is performed using `operator<`. Note
    // that capital letters ("A-Z") have ASCII values less than lowercase letters
    // ("a-z").
    template<typename Sequence1, typename Sequence2>
    bool c_lexicographical_compare(Sequence1&& sequence1, Sequence2&& sequence2)
    {
        return std::lexicographical_compare(
            container_algorithm_internal::c_begin(sequence1),
            container_algorithm_internal::c_end(sequence1),
            container_algorithm_internal::c_begin(sequence2),
            container_algorithm_internal::c_end(sequence2)
        );
    }

    // Overload of c_lexicographical_compare() for performing a lexicographical
    // comparison using a `comp` operator instead of `operator<`.
    template<typename Sequence1, typename Sequence2, typename LessThan>
    bool c_lexicographical_compare(Sequence1&& sequence1, Sequence2&& sequence2, LessThan&& comp)
    {
        return std::lexicographical_compare(
            container_algorithm_internal::c_begin(sequence1),
            container_algorithm_internal::c_end(sequence1),
            container_algorithm_internal::c_begin(sequence2),
            container_algorithm_internal::c_end(sequence2),
            std::forward<LessThan>(comp)
        );
    }

    // c_next_permutation()
    //
    // Container-based version of the <algorithm> `std::next_permutation()` function
    // to rearrange a container's elements into the next lexicographically greater
    // permutation.
    template<typename C>
    bool c_next_permutation(C& c)
    {
        return std::next_permutation(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_next_permutation() for performing a lexicographical
    // comparison using a `comp` operator instead of `operator<`.
    template<typename C, typename LessThan>
    bool c_next_permutation(C& c, LessThan&& comp)
    {
        return std::next_permutation(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    // c_prev_permutation()
    //
    // Container-based version of the <algorithm> `std::prev_permutation()` function
    // to rearrange a container's elements into the next lexicographically lesser
    // permutation.
    template<typename C>
    bool c_prev_permutation(C& c)
    {
        return std::prev_permutation(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c));
    }

    // Overload of c_prev_permutation() for performing a lexicographical
    // comparison using a `comp` operator instead of `operator<`.
    template<typename C, typename LessThan>
    bool c_prev_permutation(C& c, LessThan&& comp)
    {
        return std::prev_permutation(container_algorithm_internal::c_begin(c), container_algorithm_internal::c_end(c), std::forward<LessThan>(comp));
    }

    //------------------------------------------------------------------------------
    // <numeric> algorithms
    //------------------------------------------------------------------------------

    // c_iota()
    //
    // Container-based version of the <algorithm> `std::iota()` function
    // to compute successive values of `value`, as if incremented with `++value`
    // after each element is written. and write them to the container.
    template<typename Sequence, typename T>
    void c_iota(Sequence& sequence, T&& value)
    {
        std::iota(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(value));
    }
    // c_accumulate()
    //
    // Container-based version of the <algorithm> `std::accumulate()` function
    // to accumulate the element values of a container to `init` and return that
    // accumulation by value.
    //
    // Note: Due to a language technicality this function has return type
    // absl::decay_t<T>. As a user of this function you can casually read
    // this as "returns T by value" and assume it does the right thing.
    template<typename Sequence, typename T>
    decay_t<T> c_accumulate(const Sequence& sequence, T&& init)
    {
        return std::accumulate(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(init));
    }

    // Overload of c_accumulate() for using a binary operations other than
    // addition for computing the accumulation.
    template<typename Sequence, typename T, typename BinaryOp>
    decay_t<T> c_accumulate(const Sequence& sequence, T&& init, BinaryOp&& binary_op)
    {
        return std::accumulate(container_algorithm_internal::c_begin(sequence), container_algorithm_internal::c_end(sequence), std::forward<T>(init), std::forward<BinaryOp>(binary_op));
    }

    // c_inner_product()
    //
    // Container-based version of the <algorithm> `std::inner_product()` function
    // to compute the cumulative inner product of container element pairs.
    //
    // Note: Due to a language technicality this function has return type
    // absl::decay_t<T>. As a user of this function you can casually read
    // this as "returns T by value" and assume it does the right thing.
    template<typename Sequence1, typename Sequence2, typename T>
    decay_t<T> c_inner_product(const Sequence1& factors1, const Sequence2& factors2, T&& sum)
    {
        return std::inner_product(container_algorithm_internal::c_begin(factors1), container_algorithm_internal::c_end(factors1), container_algorithm_internal::c_begin(factors2), std::forward<T>(sum));
    }

    // Overload of c_inner_product() for using binary operations other than
    // `operator+` (for computing the accumulation) and `operator*` (for computing
    // the product between the two container's element pair).
    template<typename Sequence1, typename Sequence2, typename T, typename BinaryOp1, typename BinaryOp2>
    decay_t<T> c_inner_product(const Sequence1& factors1, const Sequence2& factors2, T&& sum, BinaryOp1&& op1, BinaryOp2&& op2)
    {
        return std::inner_product(container_algorithm_internal::c_begin(factors1), container_algorithm_internal::c_end(factors1), container_algorithm_internal::c_begin(factors2), std::forward<T>(sum), std::forward<BinaryOp1>(op1), std::forward<BinaryOp2>(op2));
    }

    // c_adjacent_difference()
    //
    // Container-based version of the <algorithm> `std::adjacent_difference()`
    // function to compute the difference between each element and the one preceding
    // it and write it to an iterator.
    template<typename InputSequence, typename OutputIt>
    OutputIt c_adjacent_difference(const InputSequence& input, OutputIt output_first)
    {
        return std::adjacent_difference(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output_first);
    }

    // Overload of c_adjacent_difference() for using a binary operation other than
    // subtraction to compute the adjacent difference.
    template<typename InputSequence, typename OutputIt, typename BinaryOp>
    OutputIt c_adjacent_difference(const InputSequence& input, OutputIt output_first, BinaryOp&& op)
    {
        return std::adjacent_difference(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output_first, std::forward<BinaryOp>(op));
    }

    // c_partial_sum()
    //
    // Container-based version of the <algorithm> `std::partial_sum()` function
    // to compute the partial sum of the elements in a sequence and write them
    // to an iterator. The partial sum is the sum of all element values so far in
    // the sequence.
    template<typename InputSequence, typename OutputIt>
    OutputIt c_partial_sum(const InputSequence& input, OutputIt output_first)
    {
        return std::partial_sum(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output_first);
    }

    // Overload of c_partial_sum() for using a binary operation other than addition
    // to compute the "partial sum".
    template<typename InputSequence, typename OutputIt, typename BinaryOp>
    OutputIt c_partial_sum(const InputSequence& input, OutputIt output_first, BinaryOp&& op)
    {
        return std::partial_sum(container_algorithm_internal::c_begin(input), container_algorithm_internal::c_end(input), output_first, std::forward<BinaryOp>(op));
    }

    ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_ALGORITHM_CONTAINER_H_