Method get8Perm

app/src/main/java/solver/Utils.java:53–62

(int[] arr, int len)

    }

    public static int get8Perm(int[] arr, int len) {
        int idx = 0;
        int val = 0x76543210;
        for (int i = 0; i < len - 1; i++) {
            int v = arr[i] << 2;
            idx = (len - i) * idx + ((val >> v) & 0x7);
            val -= 0x11111110 << v;
        }
        return idx;
    }

    static void set11Perm(int[] arr, int idx, int len) {
        long val = 0xa9876543210L;