Comment by whimsicalism
3 years ago
Yes, companies are hiring for competency not tenure or years of life lived while holding job. If you want the latter, I have heard it is more structured that way in Japan and much of Europe.
I would expect most people I hire to be able to explain how a hash map works.
Depends on what exactly your company is doing? Why do you care if an applicant understand how a hash map works; and what's particular about a hash map?
I'd care more about an applicant understanding the concept of a hash; or hashing in general. If an applicant shows that he understands that a hash is a magical and fascinating mathematical concept; and it can have uses in Information/Computers, that would be more interesting (to me) than someone who memorized a hash map definition.
He can always learn about a particular application of hashing (hash map, for example). But the latter shows aptitude and capacity to learn these later on the job.
> why do you care if an applicant understand how a hash map works; and what's particular about a hash map?
Because a hash map is:
1) a pretty basic concept in data structures
2) Variations on hash maps are used all the time in the real world. If you use objects in javascript, dictionaries in python, or maps in C++, then you are using things that essentially implement hash maps.
Point number 1 is like if I went to an orthopedic surgeon and they couldn't tell me what the liver does. You can say "well the liver has nothing to do with my finger that got smashed in a car crash, so what do I care." Or you can say, "that seems like a red flag. Maybe I'd be safer choosing a different doctor."
* Note: I have no idea how often the liver comes up in orthopedic finger surgery and for all I know it's a lot. But I think you get the point.
>Variations on hash maps are used all the time
Yes, you use them. You don't build them. To torture your analogy it's like asking the surgeon to explain how their bone saw works. Why should they know? All they care is that it cuts bone.
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To me, "what a hashmap is" is just an extremely basic engineering concept. Your reference to "memorizing" (to refer to the topic you don't like) vs. "understanding" (to refer to the topic you do like) is value-laden and also suggests to me that you think a hashmap is more complicated than it actually is - it is truly just one step from understanding what a hash is.
well I mean there is quite a lot of differences between what the answer to 'what is a hashmap?' can be - is it acceptable to say a hashmap is a bunch of key value pairs where the key is an identifier by which you can look up the value you want - or should it be more in depth - akin to the wikipedia article https://en.wikipedia.org/wiki/Hash_table describing not just what it is but also its place in CS and how it is implemented? If the second it's probable the memorized description would be accurate.
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Yes, companies are hiring for competency not tenure or years of life lived while holding job.
Oh I wasn't trying to say that this knowledge was valuable or not. I was just pointing out that you seem surprised that experienced people wouldn't be able to provide a good answer to that question. And the answer is that in many jobs, its not useful knowledge.