/usr/include/SFCGAL/algorithm/ is in libsfcgal-dev 1.3.0-4+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/SFCGAL/algorithm/BoundaryVisitor.h
/usr/include/SFCGAL/algorithm/ConsistentOrientationBuilder.h
/usr/include/SFCGAL/algorithm/area.h
/usr/include/SFCGAL/algorithm/collect.h
/usr/include/SFCGAL/algorithm/collectionExtract.h
/usr/include/SFCGAL/algorithm/collectionHomogenize.h
/usr/include/SFCGAL/algorithm/collectionToMulti.h
/usr/include/SFCGAL/algorithm/connection.h
/usr/include/SFCGAL/algorithm/convexHull.h
/usr/include/SFCGAL/algorithm/covers.h
/usr/include/SFCGAL/algorithm/difference.h
/usr/include/SFCGAL/algorithm/differencePrimitives.h
/usr/include/SFCGAL/algorithm/distance.h
/usr/include/SFCGAL/algorithm/distance3d.h
/usr/include/SFCGAL/algorithm/extrude.h
/usr/include/SFCGAL/algorithm/force2D.h
/usr/include/SFCGAL/algorithm/force3D.h
/usr/include/SFCGAL/algorithm/intersection.h
/usr/include/SFCGAL/algorithm/intersects.h
/usr/include/SFCGAL/algorithm/isValid.h
/usr/include/SFCGAL/algorithm/length.h
/usr/include/SFCGAL/algorithm/minkowskiSum.h
/usr/include/SFCGAL/algorithm/normal.h
/usr/include/SFCGAL/algorithm/offset.h
/usr/include/SFCGAL/algorithm/orientation.h
/usr/include/SFCGAL/algorithm/plane.h
/usr/include/SFCGAL/algorithm/straightSkeleton.h
/usr/include/SFCGAL/algorithm/tesselate.h
/usr/include/SFCGAL/algorithm/translate.h
/usr/include/SFCGAL/algorithm/union.h
/usr/include/SFCGAL/algorithm/volume.h