I'm really confused. Is it possible to use trees like binary trees or data structures in Unity?
I need to introduce artificial intelligence into my game, and use the A* algorithm.
Sure it's possible to use trees! Just to name a few, we use...
Behaviour Trees for expressing flexible artificial intelligence logic for NPCs.
Game Trees for planning by AI opponents or hint systems.
As Tyyppi_77 notes in a comment above, it's hard to imagine a useful programming system in which it's not possible to use trees. Have you encountered any difficulty implementing a particular tree-based algorithm that you're looking for help with?