> Still I will score quite low in job interview questions ...
> I never "studied" computer science in a regular way,
You never really mentioned algorithms, and your only mention of data structures was "usage of [hash tables] instead of searching arrays and many other small things that actually enhance the code performance."
While you don't need them all the time, a good understanding of common data structures and algorithms will make you a better engineer, and I suspect this is the weakness they're seeing.
> I never "studied" computer science in a regular way,
You never really mentioned algorithms, and your only mention of data structures was "usage of [hash tables] instead of searching arrays and many other small things that actually enhance the code performance."
While you don't need them all the time, a good understanding of common data structures and algorithms will make you a better engineer, and I suspect this is the weakness they're seeing.