max_distance.hxx

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/*===========================================================================================================
 *
 * HUC - Hurna Core
 *
 * Copyright (c) Michael Jeulin-Lagarrigue
 *
 *  Licensed under the MIT License, you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://github.com/Hurna/Hurna-Core/blob/master/LICENSE
 *
 * 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.
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 *=========================================================================================================*/
#ifndef MODULE_SEARCH_MAX_DISTANCE_HXX
#define MODULE_SEARCH_MAX_DISTANCE_HXX

// STD includes
#include <iterator>
#include <utility>

namespace huc
{
  namespace search
  {
    template <typename IT, typename Distance = std::minus<typename std::iterator_traits<IT>::value_type>>
    std::pair<int, int> MaxDistance(const IT& begin, const IT& end)
    {
      if (std::distance(begin, end) < 2)
        return std::pair<int, int>(-1, -1);

      int minValIdx = 0;
      std::pair<int, int> indexes(minValIdx, 1);
      auto maxDist = Distance()(*begin, *(begin + 1));

      for (auto it = begin + 1; it != end; ++it)
      {
        const auto currentIdx = static_cast<const int>(std::distance(begin, it));

        // Keeps track of the minimum value index
        if (*it < *(begin + minValIdx))
          minValIdx = currentIdx;

        // Keeps track of the largest distance and the indexes
        const auto distance = Distance()(*it, *(begin + minValIdx));
        if (distance > maxDist)
        {
          maxDist = distance;
          indexes.first = minValIdx;
          indexes.second = currentIdx;
        }
      }

      return indexes;
    }
  }
}

#endif // MODULE_COLLECTIONS_SEARCH_HXX