I am a full-time programmer and don't have a degree in CS. I intend to learn Scheme and have been working my way using this book https://www.amazon.com/Concrete-Abstractions-Introduction-Computer-Science/dp/0534952119.

I had a aim to solve all exercises so it was going well until I got stuck in one of the exercises in Chapter 7. I found it non-trivial and though I let the problem cook in the back of my head for more than a month but I couldn't solve it.

Now this is effecting me because a)- I am feeling like giving up on this book, because I wanted to solve all exercises and now it seems I cannot b)- after this book I planned to finish SICP but now I think if I cannot solve this one may be I cannot finish SICP as well c)- and I am also beginning to doubt my abilities as a programmer.

So I need help from people who learned Scheme (using this book or SICP or at MIT) or who are master of their arts---is it okay if you're unable to solve few problems in the book? Should I carry on and finish the book?

Part of me says I should carry on and finish whatever exercises I can solve but it's sort of discouraging that I am unable to solve a problem after a decent industry experience :(