is_partitioned.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_ALGORITHM_IS_PARTITIONED_HPP
#define TETL_ALGORITHM_IS_PARTITIONED_HPP
 
namespace etl {
 
/// \brief Returns true if all elements in the range `[first, last)` that
/// satisfy the predicate p appear before all elements that don't. Also returns
/// true if the range is empty.
///
/// https://en.cppreference.com/w/cpp/algorithm/is_partitioned
///
/// \ingroup algorithm
template <typename InputIt, typename Predicate>
[[nodiscard]] constexpr auto is_partitioned(InputIt first, InputIt last, Predicate p) -> bool
{
    for (; first != last; ++first) {
        if (not p(*first)) {
            break;
        }
    }
 
    for (; first != last; ++first) {
        if (p(*first)) {
            return false;
        }
    }
 
    return true;
}
 
} // namespace etl
 
#endif // TETL_ALGORITHM_IS_PARTITIONED_HPP