Depends strongly on how you define “know”-in that context I perceive it as referring to having or gaining some basic conceptual comprehension of the concept or

Depends strongly on how you define “know”-in that context I perceive it as referring to having or gaining some basic conceptual comprehension of the concept or algorithm, particularly in order to eschew reinventing the wheel in a squared shape, and thereby unnecessarily exhibiting exponential complexity. It also depends on your field of work. “Knowing” of them would tell one where to look and how to think.