Question

I would like to know how to get the total height of a binary tree.

This is how far I came before I started to error loop in my head.

height( leaf(_), 1 ).
height( branch(Branch1, Branch2), H ):-
    height(Branch1, H1),
    height(Branch2, H2),
    is max(H1, H2).

I think I’m on the right track but I can’t seem to wrap my head around this last part (since those variables can’t be changed once a value has been set).

Answer 1

Well, you’re almost there. I don’t see much to say since what you wrote already is pretty correct, so I’ll just finish the job.

height( leaf(_), 1 ).
height( branch(Branch1, Branch2), H ):-
    height(Branch1, H1),
    height(Branch2, H2),
    H is max(H1, H2) + 1.