Shikaku Solver in Copris

This page presents a Shikaku solver written in Copris, a Constraint Programming DSL (Domain-Specific Language) embedded in Scala. Shikaku is a puzzle game developed by Nikoli.

This Shikaku solver can find a solution of the given Shikaku puzzle.

Version 2.0

• Scala jar file: ../build/copris-puzzles-2.0.jar (1575981 bytes)
• Source file: ../build/copris-puzzles-src-2.0.zip (29766 bytes)

• Scala version 2.12 to be installed
  • Other Scala version is not binary compatible with version 2.12.
• Copris (included in the package)
• Sugar (included in the package)
• Sat4j Core (included in the package)

scala -cp copris-puzzles-2.0.jar shikaku.Solver input_file_name

• The format of the input file is explained below.

To check the uniqueness of the solutions, please use "-o multi" option.

scala -cp copris-puzzles-2.0.jar shikaku.Solver -o multi input_file_name

If you have a SAT solver (such as MiniSat, GlueMiniSat) installed on your computer, you can use it to get better performance. Specify the full path of the SAT solver program with "-s1" or "-s2" option.

scala -cp copris-puzzles-2.0.jar shikaku.Solver -o multi -s2 minisat input_file_name

Solver performance is measured on version 2.0.

• Copris solver was run on Intel Xeon 3.6Hz machine with:
  • Ubuntu Linux 20.04 (64 bit)
  • Java version "1.8.0_275", OpenJDK Runtime Environment (with "-Xmx2G" option)
  • Scala version 2.12.5
  • Copris version 2.3.1
  • Sugar version 2.3.4
• GlueMiniSat version 2.2.10 (with preprocessing) is used as a SAT solver.

The following shows the source code of the solver (Shikaku.scala).

 1:  /*
 2:   * Shikaku Solver in Copris
 3:   * by Naoyuki Tamura
 4:   * http://bach.istc.kobe-u.ac.jp/copris/puzzles/shikaku/
 5:   */
 6:  package shikaku
 7:  
 8:  import jp.kobe_u.copris._
 9:  import jp.kobe_u.copris.dsl._
10:  import puzzle._
11:  
12:  case class Shikaku(m: Int, n: Int, board: Seq[Seq[String]]) extends BoardPuzzle {
13:    def isBlank(cell: Cell) = at(cell) == "-"
14:    def sizes(cell: Cell) = {
15:      val a = num(cell)
16:      for (h <- 1 to a; if a % h == 0) yield (h, a / h)
17:    }
18:    def show(sol: Seq[(Cell,(Int,Int))]) {
19:      val map = (
20:        for {
21:          k <- 0 until sol.size
22:          ((r,c),(h,w)) = sol(k)
23:          i <- r until r+h; j <- c until c+w
24:        } yield (i,j) -> k
25:      ).toMap
26:      def s(i: Int, j: Int) = map.getOrElse((i,j), -1)
27:      for (i <- 0 to m) {
28:        for (j <- 0 until n) {
29:          print("+")
30:          if (s(i,j) != s(i-1,j)) print("---")
31:          else print("   ")
32:        }
33:        println("+")
34:        if (i < m) {
35:          for (j <- 0 until n) {
36:            if (s(i,j) != s(i,j-1)) print("|")
37:            else print(" ")
38:            if (isNumber(i, j)) print("%3d".format(num(i, j)))
39:            else print("   ")
40:          }
41:          println("|")
42:        }
43:      }
44:    }
45:  }
46:  
47:  object Solver extends BoardPuzzleSolver[Shikaku] {
48:    val name = "shikaku.Solver"
49:  
50:    def puzzleFactory(m: Int, n: Int, board: Seq[Seq[String]]) =
51:      Shikaku(m, n, board)
52:  
53:    def define = {
54:      for (k <- 0 until puzzle.numberCells.size; cell = puzzle.numberCells(k)) {
55:        int('r(k), 0, puzzle.m-1)
56:        int('c(k), 0, puzzle.n-1)
57:        int('h(k), puzzle.sizes(cell).map(_._1).toSet)
58:        int('w(k), puzzle.sizes(cell).map(_._2).toSet)
59:        for ((h,w) <- puzzle.sizes(cell))
60:          add(('h(k) === h) <==> ('w(k) === w))
61:        add('r(k) + 'h(k) <= puzzle.m)
62:        add('c(k) + 'w(k) <= puzzle.n)
63:        val (i,j) = cell
64:        add(('r(k) <= i) && ('r(k) + 'h(k) > i))
65:        add(('c(k) <= j) && ('c(k) + 'w(k) > j))
66:      }
67:      for (k1 <- 0 until puzzle.numberCells.size; k2 <- k1+1 until puzzle.numberCells.size)
68:        add(('r(k1) + 'h(k1) <= 'r(k2)) || ('r(k2) + 'h(k2) <= 'r(k1)) || 
69:            ('c(k1) + 'w(k1) <= 'c(k2)) || ('c(k2) + 'w(k2) <= 'c(k1)))
70:    }
71:  
72:    def showSolution {
73:      val sol = for (k <- 0 until puzzle.numberCells.size)
74:                yield ((solution('r(k)),solution('c(k))), (solution('h(k)),solution('w(k))))
75:      if (quiet == 0) {
76:        println("Solution = " + sol)
77:        println("Size = " + sol.size)
78:        puzzle.show(sol)
79:      }
80:    }
81:  }

• It should be compiled with ../build/PuzzleSolver.scala.

This software is distributed under the BSD 3-Clause License. See LICENSE.

• Copris (Constraint Programming DSL embedded in Scala)
• Sugar (an award winning Constraint Solver)
  • Default constraint solver used in Copris
• Sat4j (SAT solver in Java)
  • Default SAT solver used in Copris
• Shikaku (by Nikoli)
• Wikipedia:Shikaku
• http://www.janko.at/Raetsel/Sikaku/