private static long hash64(long x, long seed) {
    x += seed;
    x = (x ^ (x >>> 33)) * 0xff51afd7ed558ccdL;
    x = (x ^ (x >>> 33)) * 0xc4ceb9fe1a85ec53L;
    x = x ^ (x >>> 33);
    return x;
  }
private static long hash64(long x, long seed)