Class Pyraminx

app/src/main/java/solver/Pyraminx.java:5–309

import java.util.Random;

public class Pyraminx {
    private static int[] colmap = new int[91];
    private static byte[] perm = new byte[360];	// pruning table for edge permutation
    private static byte[] twst = new byte[2592];	// pruning table for edge orientation+twist
    private static short[][] permmv = new short[360][4];	// transition table for edge permutation
    private static short[][] twstmv = new short[81][4];	// transition table for corner orientation
    private static short[][] flipmv = new short[32][4];	// transition table for edge orientation
    private static String[] turn = {"L", "R", "B", "U"};
    private static String[] suff = {"'", ""};
    private static String[] tips = {"l", "r", "b", "u"};
    //private static int[] seq = new int[12];
    private static int[] img = new int[91];
    private static Random r = new Random();

    static {
        calcperm();
    }

    public static String scramble() {
        String scramble;
        do {
            int t = r.nextInt(2592), q = r.nextInt(360);
            scramble = scramble(q, t);
        } while (scramble.equals("error"));
        return scramble;
    }

    public static String scrambleL4E() {
        String scramble;
        do {
            int[] ps = {0, 1, 2, 3, 4, 5};
            Utils.idxToPerm(ps, r.nextInt(12), 4, true);
            int[] ts = new int[6];
            Utils.idxToFlip(ts, r.nextInt(8), 4, true);
            int p = Utils.permToIdx(ps, 6, true);
            int t = r.nextInt(3) * 864 + Utils.flipToIdx(ts, 6, true);
            scramble = scramble(p, t);
        } while (scramble.equals("error"));
        return scramble;
    }

    private static String scramble(int p, int t) {
        int[] seq = new int[12];
        for (int l = 0; l < 12; l++)
            if (search(p, t, l, -1, seq)) {
                if (l < 2) return "error";
                if (l < 5) {
                    continue;
                }
                StringBuilder sol = new StringBuilder();
                for (int i = 1; i <= l; i++)
                    sol.append(turn[seq[i] >> 1]).append(suff[seq[i] & 1]).append(" ");
                for (int i = 0; i < 4; i++) {
                    int j = r.nextInt(3);
                    if (j < 2)
                        sol.append(tips[i]).append(suff[j]).append(" ");
                }
                return sol.toString();