Method resolvePerm

app/src/main/java/cs/min2phase/Tools.java:159–196

(int[] arr, int cntU, int parity)

    }

    private static int resolvePerm(int[] arr, int cntU, int parity) {
        if (arr == STATE_SOLVED) {
            return 0;
        } else if (arr == STATE_RANDOM) {
            return parity == -1 ? gen.nextInt(2) : parity;
        }
        byte[] val = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] != -1) {
                val[arr[i]] = -1;
            }
        }
        int idx = 0;
        for (int i = 0; i < arr.length; i++) {
            if (val[i] != -1) {
                int j = gen.nextInt(idx + 1);
                byte temp = val[i];
                val[idx++] = val[j];
                val[j] = temp;
            }
        }
        int last = -1;
        for (idx = 0; idx < arr.length && cntU > 0; idx++) {
            if (arr[idx] == -1) {
                if (cntU == 2) {
                    last = idx;
                }
                arr[idx] = val[--cntU];
            }
        }
        int p = Util.getNParity(Util.getNPerm(arr, arr.length), arr.length);
        if (p == 1 - parity && last != -1) {
            int temp = arr[idx - 1];
            arr[idx - 1] = arr[last];
            arr[last] = temp;
        }
        return p;
    }

    public static final int[] STATE_RANDOM = null;
    public static final int[] STATE_SOLVED = new int[0];