Labeling a rectilinear map with sliding labels

A redilinear map consists of a set of mutually non-intersecting rectilinear (i.e., horizontal or vertical) line segments, and each segment is allowed to use a rectangular label of height B and length the same as the segment. Sliding labels are not restricted to any finite number of predefined positi ons but can slide and be placed at any position as long as it intersects th e segment. This paper considers three versions of the problem of labeling a rectilinear map with sliding labels and presents efficient exact and appro ximation algorithms for them.