SOFSEM 2013: Theory and Practice of Computer Science : 39th Conference on Current Trends in Theory and Practice of Computer Science Špindlerův Mlýn, Czech Republic January 26-31, 2013 Proceedings Vol. II - Boas, Peter Van Emde; Groen, Frans C.A; Italiano, Giuseppe F.; Nawrocki, Jerzy R.; Sack, Harald (Institute of Computer Science AS CR, 2013)