"Can you offer an example of specific situation, in any OO-language with reasonable amount of available libraries, where deep knowledge of design and analysis o

"Can you offer an example of specific situation, in any OO-language with reasonable amount of available libraries, where deep knowledge of design and analysis of algorithms is actually required?" You won't get very many good replies because you are asking the wrong questions. The truth is you don't even need a decent understanding of OO for most day to day dev. You will just produce suboptimal work. A better question is: "...where reasonable knowledge of design and analysis of algorithms allows you to do a better job?" And the answer to this more reasonable question is: Every single project I've worked on as an enterprise developer over the last 10+ years. Being able to say "hey actually this problem we are working on can be formulated as a graph problem" can turn a 3 month problem into a 3 day problem. For example we recently had a rules engine rule dependency issue that turned out to be expressable as graph problem and was then easily solved. If nobody in the team had a good knowledge of algorithms we still could have solved the issue but it just would have taken a lot longer. And unfortunately until you can phrase the problem in the right way you can't just google "find best algorithm for XYZ".