是否有强大的Bentley-Ottmann算法的C++实现？

Question

Bentley-Ottoman算法查找一组线段中的所有交叉点.对于一个众所周知且重要的算法,Bentley-Ottmann算法的C++实现似乎很奇怪 - 可以处理所有退化情况的实现(即,对扫描线和交叉点的数量没有特殊假设,等等on) - 根本没有.我能找到的唯一代码就在这里,但它似乎没有处理广义的情况.

Bentley-Ottmann算法是否已经在任何经过​​良好测试的库中实现,例如Boost或LEDA？如果是的话,我可以参考吗？

Answer 1

CGAL在那里有一些与Bentley-Ottmann相同的复杂性,O((n + k)*log(n))其中n是段k的数量和交叉点的数量(不确定它们使用哪种算法):

//! \file examples/Arrangement_on_surface_2/sweep_line.cpp
// Computing intersection points among curves using the sweep line.

#include <CGAL/Cartesian.h>
#include <CGAL/MP_Float.h>
#include <CGAL/Quotient.h>
#include <CGAL/Arr_segment_traits_2.h>
#include <CGAL/Sweep_line_2_algorithms.h>
#include <list>

typedef CGAL::Quotient<CGAL::MP_Float>                  NT;
typedef CGAL::Cartesian<NT>                             Kernel;
typedef Kernel::Point_2                                 Point_2;
typedef CGAL::Arr_segment_traits_2<Kernel>              Traits_2;
typedef Traits_2::Curve_2                               Segment_2;

int main()
{
  // Construct the input segments.
  Segment_2 segments[] = {Segment_2 (Point_2 (1, 5), Point_2 (8, 5)),
                          Segment_2 (Point_2 (1, 1), Point_2 (8, 8)),
                          Segment_2 (Point_2 (3, 1), Point_2 (3, 8)),
                          Segment_2 (Point_2 (8, 5), Point_2 (8, 8))};

  // Compute all intersection points.
  std::list<Point_2>     pts;

  CGAL::compute_intersection_points (segments, segments + 4,
                                     std::back_inserter (pts));

  // Print the result.
  std::cout << "Found " << pts.size() << " intersection points: " << std::endl; 
  std::copy (pts.begin(), pts.end(),
             std::ostream_iterator<Point_2>(std::cout, "\n"));

  // Compute the non-intersecting sub-segments induced by the input segments.
  std::list<Segment_2>   sub_segs;

  CGAL::compute_subcurves(segments, segments + 4, std::back_inserter(sub_segs));

  std::cout << "Found " << sub_segs.size()
            << " interior-disjoint sub-segments." << std::endl;

  CGAL_assertion (CGAL::do_curves_intersect (segments, segments + 4));

  return 0;
}

http://doc.cgal.org/latest/Sweep_line_2/index.html