There can be many strategies. The computer does NOT know what cards you placed, but it will try to learn your strategies after he takes the cards you placed on the table. He’ll also try to detect to which of his strategies you respond badly (wrongly guess “Liar”).
You should try to learn his strategies and see if you can beat him.
The computer will first try some random strategies against you. Then after a while it will try to build your “psychological profile” so as to better guess what strategies to play with you.
Remember: the best strategy is a changing one. But then again, remember the computer knows this too...