Abstract
We consider the following generalization of the popular “15 puzzle.” Let T be a tree with n vertices and with k < n distinct pebbles numbered 1, ..., k on distinct vertices. A move consists in transferring a pebble from its current position to an adjacent unoccupied vertex. We ask the following question: Is a given arrangement of pebbles reachable from another?
We present an algorithm that on input two arrangements of k pebbles on a tree with n vertices decides in time O(n) whether the two arrangements are reachable from one another. We also give an algorithm that, on input two reachable configurations, return a sequence of moves that transforms one configuration into the other.
The pebble motion problem on trees has various applications including memory management in distributed systems, robot motion planning, and deflection routing.
Partially supported by Progetto MURST 40%, Algoritmi, Modelli di Calcolo e Strutture Informative. Part of this work was done while the last author was at International Computer Science Institute, Berkeley, CA, USA.
Preview
Unable to display preview. Download preview PDF.
References
V. Auletta, D. Parente, G. Persiano, Optimal Planning of Robot Motion on a Tree with Obstacles, T.R. 18, Dip. Informatica ed Applicazioni, Univ. di Salerno, 1995.
D. Kornhauser, G. Miller, and P. Spirakis, Coordinating pebble motion on graphs, the diameter of permutations groups, and applications, in Proc. of 25-th IEEE Symp. on Found. of Comp. Sc., 241–250, 1984.
C. Papadimitriou, P. Raghavan, M. Sudan and H. Tamaki, Motion Planning on a graph, in Proc. of 35-th IEEE Symp. on Found, of Comp. Sc., 511–520, 1994.
D. Ratner and M. Warmuth, The (n 2 − 1)-Puzzle and Related Relocation Problems, Journal of Symbolic Computation, 10:111–137, 1990.
J.T. Schwartz, M. Sharir, and J. Hopcroft, Planning, Geometry, and Complexity of Robot Motion, Ablex, Norwood NJ, 1987.
R. M. Wilson, Graph puzzles, homotopy, and the alternating group, Journal of Comb. Theory Series B, 16, 86–94, 1974.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1996 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Auletta, V., Monti, A., Parente, M., Persiano, P. (1996). A linear time algorithm for the feasibility of pebble motion on trees. In: Karlsson, R., Lingas, A. (eds) Algorithm Theory — SWAT'96. SWAT 1996. Lecture Notes in Computer Science, vol 1097. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-61422-2_137
Download citation
DOI: https://doi.org/10.1007/3-540-61422-2_137
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-61422-7
Online ISBN: 978-3-540-68529-6
eBook Packages: Springer Book Archive