min2phase

Rubik's Cube solver or scrambler.

Usage

import cs.min2phase.Search;
import cs.min2phase.Tools;

public class demo {

    public static void simpleSolve(String scrambledCube) {
        String result = new Search().solution(scrambledCube, 21, 100000000, 0, 0);
        System.out.println(result);
        // R2 U2 B2 L2 F2 U' L2 R2 B2 R2 D  B2 F  L' F  U2 F' R' D' L2 R'
    }

    public static void outputControl(String scrambledCube) {
        String result = new Search().solution(scrambledCube, 21, 100000000, 0, Search.APPEND_LENGTH);
        System.out.println(result);
        // R2 U2 B2 L2 F2 U' L2 R2 B2 R2 D  B2 F  L' F  U2 F' R' D' L2 R' (21f)

        result = new Search().solution(scrambledCube, 21, 100000000, 0, Search.USE_SEPARATOR | Search.INVERSE_SOLUTION);
        System.out.println(result);
        // R  L2 D  R  F  U2 F' L  F' .  B2 D' R2 B2 R2 L2 U  F2 L2 B2 U2 R2
    }

    public static void findShorterSolutions(String scrambledCube) {
        //Find shorter solutions (try more probes even a solution has already been found)
        //In this example, we try AT LEAST 10000 phase2 probes to find shorter solutions.
        String result = new Search().solution(scrambledCube, 21, 100000000, 10000, 0);
        System.out.println(result);
        // L2 U  D2 R' B  U2 L  F  U  R2 D2 F2 U' L2 U  B  D  R'
    }

    public static void continueSearch(String scrambledCube) {
        //Continue to find shorter solutions
        Search searchObj = new Search();
        String result = searchObj.solution(scrambledCube, 21, 500, 0, 0);
        System.out.println(result);
        // R2 U2 B2 L2 F2 U' L2 R2 B2 R2 D  B2 F  L' F  U2 F' R' D' L2 R'

        result = searchObj.next(500, 0, 0);
        System.out.println(result);
        // D2 L' D' L2 U  R2 F  B  L  B  D' B2 R2 U' R2 U' F2 R2 U' L2

        result = searchObj.next(500, 0, 0);
        System.out.println(result);
        // L' U  B  R2 F' L  F' U2 L  U' B' U2 B  L2 F  U2 R2 L2 B2

        result = searchObj.next(500, 0, 0);
        System.out.println(result);
        // Error 8, no solution is found after 500 phase2 probes. Let's try more probes.

        result = searchObj.next(500, 0, 0);
        System.out.println(result);
        // L2 U  D2 R' B  U2 L  F  U  R2 D2 F2 U' L2 U  B  D  R'
    }

    public static void main(String[] args) {
        // Full initialization, which will take about 200ms.
        // The solver will be about 5x~10x slower without full initialization.
        long startTime = System.nanoTime();
        Search.init();
        System.out.println("Init time: " + (System.nanoTime() - startTime) / 1.0E6 + " ms");

        /** prepare scrambledCube as
         *
         *             |************|
         *             |*U1**U2**U3*|
         *             |************|
         *             |*U4**U5**U6*|
         *             |************|
         *             |*U7**U8**U9*|
         *             |************|
         * ************|************|************|************|
         * *L1**L2**L3*|*F1**F2**F3*|*R1**R2**R3*|*B1**B2**B3*|
         * ************|************|************|************|
         * *L4**L5**L6*|*F4**F5**F6*|*R4**R5**R6*|*B4**B5**B6*|
         * ************|************|************|************|
         * *L7**L8**L9*|*F7**F8**F9*|*R7**R8**R9*|*B7**B8**B9*|
         * ************|************|************|************|
         *             |************|
         *             |*D1**D2**D3*|
         *             |************|
         *             |*D4**D5**D6*|
         *             |************|
         *             |*D7**D8**D9*|
         *             |************|
         *
         * -> U1 U2 ... U9 R1 ... R9 F1 ... F9 D1 ... D9 L1 ... L9 B1 ... B9
         */
        String scrambledCube = "DUUBULDBFRBFRRULLLBRDFFFBLURDBFDFDRFRULBLUFDURRBLBDUDL";
        // scrambledCube can also be obtained by specific moves
        scrambledCube = Tools.fromScramble("R L2 D R F U2 F' L F' B2 D' R2 B2 R2 L2 U F2 L2 B2 U2 R2");
        System.out.println(scrambledCube);

        simpleSolve(scrambledCube);
        outputControl(scrambledCube);
        findShorterSolutions(scrambledCube);
        continueSearch(scrambledCube);
    }
}

License GPLv3

Copyright (C) 2023  Shuang Chen

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

License MIT

Copyright (c) 2023 Chen Shuang

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.