These data files correspond to the experiments reported in Section 4 of the following paper: P. Biro, D.F. Manlove and I. McBride. The Hospitals / Residents problem with Couples: Complexity and Integer Programming models. In Proceedings of SEA 2014: the 13th International Symposium on Experimental Algorithms, volume 8504 of Lecture Notes in Computer Science, pages 10-21, Springer, 2014. Publisher final version: http://dx.doi.org/10.1007/978-3-319-07959-2_2 Author final version: http://eprints.gla.ac.uk/97774 The data in folder "Varying Number of Hospitals" refer to the experiment described on Page 19 (results reported in Figure 1 on Page 19). The data in folder "Varying Pref List Length" refer to the experiment described on Page 20 (results reported in Figure 2 on Page 20). Each instance file name is in the following format: - - - - - - - - - .txt Each instance file contains the following data: <2x preference lists for the residents who are involved in a couple> Resident and hospital IDs count from 0. Residents 0,1,...,2x-1 are the residents who are involved in a couple, and the couples comprise resident pairs (2i,2i+1) (0<=i<=x-1). The preference lists of the residents involved in couple (2i,2i+1) are in the following format: ... ... This means that the joint preference list for the couple (2i,2i+1) is then: ... The preference lists of the single residents are in the following format: ... The preference lists of the hospitals are in the following format: first-choice resident ID> ...