Class HalfTurn

app/src/main/java/solver/HalfTurn.java:9–127

import static solver.Utils.swap;

public class HalfTurn {
    private static short[][] cpm = new short[24][6];
    private static short[][][] epm = new short[3][24][6];
    private static byte[] cpd = new byte[24 * 24];
    private static byte[][][] epd = new byte[24][24][24];
    private static int[] seq = new int[21];

    static {
        int[] temp = new int[4];
        for (int i = 0; i < 24; i++) {
            for (int j = 0; j < 6; j++) {
                Utils.idxToPerm(temp, i, 4, false);
                switch (j) {
                    case 0: swap(temp, 0, 1); break;
                    case 1: swap(temp, 2, 3); break;
                    case 2: swap(temp, 0, 2); break;
                    case 3: swap(temp, 1, 3); break;
                    case 4: swap(temp, 1, 2); break;
                    case 5: swap(temp, 0, 3); break;
                }
                cpm[i][j] = (byte) Utils.permToIdx(temp, 4, false);
                Utils.idxToPerm(temp, i, 4, false);
                switch (j) {
                    case 0: swap(temp, 0, 1); break;
                    case 1: swap(temp, 2, 3); break;
                    case 2: swap(temp, 0, 3); break;
                    case 3: swap(temp, 1, 2); break;
                }
                epm[0][i][j] = (byte) Utils.permToIdx(temp, 4, false);
                Utils.idxToPerm(temp, i, 4, false);
                switch (j) {
                    case 0: swap(temp, 0, 1); break;
                    case 1: swap(temp, 2, 3); break;
                    case 4: swap(temp, 0, 3); break;
                    case 5: swap(temp, 1, 2); break;
                }
                epm[1][i][j] = (byte) Utils.permToIdx(temp, 4, false);
                Utils.idxToPerm(temp, i, 4, false);
                switch (j) {
                    case 2: swap(temp, 0, 3); break;
                    case 3: swap(temp, 1, 2); break;
                    case 4: swap(temp, 0, 1); break;
                    case 5: swap(temp, 2, 3); break;
                }
                epm[2][i][j] = (byte) Utils.permToIdx(temp, 4, false);
            }
        }
        for (int i = 1; i < 576; i++) cpd[i] = -1;
        cpd[0] = 0;
        Utils.createPrun(cpd, 3, cpm, cpm, 1);
        for (int i = 0; i < 24; i++)
            for (int j = 0; j < 24; j++)
                for (int k = 0; k < 24; k++)
                    epd[i][j][k] = -1;
        epd[0][0][0] = 0;
        int c = 1;
        for (int d = 0; d < 8; d++) {
            //c = 0;