Yes, I think this is more of a retrieval issue than a memory issue. I have memories of most of the things I did in my work and studies, but I can't retrieve the

Yes, I think this is more of a retrieval issue than a memory issue. I have memories of most of the things I did in my work and studies, but I can't retrieve them based on an abstract query like "a difficult problem." When I get a question like this, I have to find a more concrete approach to retrieve things I did (e.g. "what kinds of problems did I work on together with Sarah in the Compiler Design class"), and then filter them for difficult things that had interesting solutions.