Horiyama, Takashi, Ito, Takehiro, Nakatsuka, Keita, Suzuki, Akira, Uehara, Ryuhei, Horiyama, Takashi, Ito, Takehiro, Nakatsuka, Keita, Suzuki, Akira, and Uehara, Ryuhei
We study the computational hardness of the tiling puzzle with polyominoes, where a polyomino is a rectilinear polygon (i.e., a polygon made by connecting unit squares.) In the tiling problem, we are given a rectilinear polygon P and a set S of polyominoes, and asked whether P can be covered without any overlap using translated copies of polyominoes in S. In this paper, we focus on trominoes and bars as polyominoes; a tromino is a polyomino consisting of three unit squares, and a bar is a rectangle of either height one or width one. Notice that there are essentially two shapes of trominoes, that is, I-shape (i.e., a bar) and L-shape. We consider the tiling problem when restricted to only L-shape trominoes, only I-shape trominoes, both L-shape and I-shape trominoes, or only two bars. In this paper, we prove that the tiling problem remains NP-complete even for such restricted sets of polyominoes. All reductions are carefully designed so that we can also prove the #P-completeness and ASP-completeness of the counting and the another-solution-problem variants, respectively.Our results answer two open questions proposed by Moore and Robson (2001) and Pak and Yang (2013)., identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/15100