If you meant to type something else, please feel free to let me know and I'll do my best to assist you.
One possibility is that 1ldkjk is a randomly generated string of characters, perhaps created by a computer algorithm or a keyboard mash. This theory is supported by the fact that the term doesn't appear to have any coherent meaning or context.
For practical needs:
If you find yourself moving into a 1LDK layout, the "JK" (the extra features) should dictate your decor: