D - One Sword image

  • Thoughts.
    • This is a pain in the ass.
    • Determine the intersection of line segments and sort the intersection points
    • Alternate because we know the chop starts from the outside.
    • Connect odd-numbered intersections with even-numbered intersections. Since we are dealing only graphically, it is sufficient to connect the two ends of the cut edges, but it is necessary to avoid twisting the edges.
      • We can’t use the inner product to determine that, so we’ll do a line segment crossing determination.
    • Once you have the edge set, just count the number of connected components.
    • I’ve got an article up to the point where I’m looking for intersections, so I’ll put it in my library later.
  • Official Explanation
    • Oh, I only counted the number of cut edges.
    • Okay, you say “polygonal” so there are no holes.
    • I thought too hard.

ABC016


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