@article{oai:barrel.repo.nii.ac.jp:00005148,
 author = {Haraguchi, Kazuya and Tanaka, Ryoya},
 journal = {Journal of Information Processing},
 month = {Aug},
 note = {The Building puzzle（a.k.a., the Skyscraper) is a Latin square completion-type puzzle like Sudoku,KenKen. and Futoshiki. Recently, Iwamoto and Matsui showed the NP-completeness of the decision problem version of this　puzzle, which asks whether a given instance has a solution or not. We provide a stronger result in the present paper;it is still NP-complete to decide whether we can complete a single line of the grid (i.e., a l×n or an n×l subgrid)without violating the rule.},
 pages = {730--734},
 title = {The Building Puzzle Is Still Hard Even in the Single Lined Version},
 volume = {25},
 year = {2017}
}