docs: int flipTriangles(long[] flippedA, long[] flippedB) {
      int numflips = 0;
      BitsUtil.zeroI(flippedB);
      for(int i = BitsUtil.nextSetBit(flippedA, 0); i > -1; i = BitsUtil.nextSetBit(flippedA, i + 1)) {
        if(!BitsUtil.get(flippedB, i) && flipTriangle(i, flippedB) >= 0) {
          numflips += 2;
        }
      }
      if(LOG.isDebuggingFinest()) {
        LOG.debugFinest("Flips: " + numflips);
      }
      return numflips;
    }