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Wow. Arrogance. He wouldn't have been hired with me. I particularly like the jab at the interviewer for not having instant recall of every single CS algorithm.

Wow. Arrogance. He wouldn't have been hired with me. I particularly like the jab at the interviewer for not having instant recall of every single CS algorithm. I keep TAOCP on my desk, and /because/ I don't know every single algorithm.

derefr 17y ago
He said the interviewer had never heard of cuckoo hashing. That's a slightly different matter than a "not having instant recall", especially for someone asking questions about how to implement hashtables in the first place (they should have looked at the relevant reference before going in to do the interview, as they were obviously following a very fixed format, instead of letting the discussion range.)
- vicaya 17y ago
  Cuckoo hashing is a relatively new but underperforming hashing scheme due to the fact it's not cache friendly for modern processors: "despite its constant worst-case look-up cost, the bucketized cuckoo hash table was demonstrated to be the slowest hash table, far inferior to both the chained and array hash tables." No, they're not asking for details of hash table implementation. The main goal is to see if you can scale the algorithm, for which they're the real experts. The hash table discussion is a mere diversion. The "expected" progression of the particular discussion is: 1. hash table implementation (simplest map container) when you have enough RAM to see if the candidate gets cs basics. 2. sort | uniq -c when you have enough disks on a single node to see if the candidate has experience with non-trivial amount of data (larger than RAM.) and understanding of modern disk performance characteristics (random vs sequential I/O) 3. map-reduce on multiple nodes for the entire internet; see if the candiate has experience and understandings with distributed computing. So the author didn't make very far. His attitude and mindset were also getting in the way of interviewers' steering the interview. It's a classic case of impedance mismatch in interviews.
visitor4rmindia 17y ago
He appears to be good at algorithms, has a feel for the actual space and time requirements, is able to think under pressure, and has a sense of humour. I'd hire him in a heartbeat.
- ErrantX 17y ago
  he fell into every trap laid out for him... (all of them classic interview traps). That would at the very least worry me... But it depends on the job :)
  - yason 17y ago
    What were these traps? I'd like to know.
    - ErrantX 17y ago
      - chasing an irrelevant point (the interviewer specifically wanted to move on. NEVER stop that, that is the one single that can cost you a job). - assuming importance (his tone suggests he thinks he knew more than the interviewer. I imagine that might have come across in the interview) - assuming ingorance (if it seems amazing the interviewer is clueless on something then it probably isnt true. Adjust appropriately.) - chasing the wrong issue (if an interviewer needs to draw an answer out - even in a fluid way like that - it will be a black mark on your notes) - assuming irrelevance (his opening remarks suggest he though the question was not relevant to the interview he was having, which suggests he possibly did not treat it with the same gravity. Everything is relevant - the more off the wall the question the more important your answer is). There are more but those were the key points I picked up: not being there and only having his side of that short portion I cant say 100% he fell into every one. But it definitely looks that way :) This is based on similar traps I set up for our interviewee's.
      - byrneseyeview 17y ago
        chasing an irrelevant point Anecdotally, when a one-hour interview turns into a three-hour discussion of a side point, it is a really good sign. If the interviewer isn't into it, give up -- but people who can bounce ideas off of each other tend to come up with more ideas.
badger7 17y ago
One definition of arrogance is "making undue claims in an overbearing manner". You know, like turning "never having heard of" into "not having instant recall of every single CS algorithm".
wglb 17y ago
Attitude is good, but it seems misdirected. For example, are you really sure that the 10,000 frequency list is going to be all that different day to day? While I like to hire people smarter than I am, I rather like to draw that conclusion myself, rather than have somebody try to wrestle me to the ground to prove it.
- huhtenberg 17y ago
  The attitude was actually quite bad considering this was an interview and not a lazy chat between two colleagues. This guy plainly failed to demonstrate that he can understand the context of the question, which was not an offer to ramble about the question not making much practical sense.

derefr 17y ago

He said the interviewer had never heard of cuckoo hashing. That's a slightly different matter than a "not having instant recall", especially for someone asking questions about how to implement hashtables in the first place (they should have looked at the relevant reference before going in to do the interview, as they were obviously following a very fixed format, instead of letting the discussion range.)

vicaya 17y ago
Cuckoo hashing is a relatively new but underperforming hashing scheme due to the fact it's not cache friendly for modern processors: "despite its constant worst-case look-up cost, the bucketized cuckoo hash table was demonstrated to be the slowest hash table, far inferior to both the chained and array hash tables." No, they're not asking for details of hash table implementation. The main goal is to see if you can scale the algorithm, for which they're the real experts. The hash table discussion is a mere diversion. The "expected" progression of the particular discussion is: 1. hash table implementation (simplest map container) when you have enough RAM to see if the candidate gets cs basics. 2. sort | uniq -c when you have enough disks on a single node to see if the candidate has experience with non-trivial amount of data (larger than RAM.) and understanding of modern disk performance characteristics (random vs sequential I/O) 3. map-reduce on multiple nodes for the entire internet; see if the candiate has experience and understandings with distributed computing. So the author didn't make very far. His attitude and mindset were also getting in the way of interviewers' steering the interview. It's a classic case of impedance mismatch in interviews.

visitor4rmindia 17y ago

He appears to be good at algorithms, has a feel for the actual space and time requirements, is able to think under pressure, and has a sense of humour. I'd hire him in a heartbeat.

ErrantX 17y ago
he fell into every trap laid out for him... (all of them classic interview traps). That would at the very least worry me... But it depends on the job :)
- yason 17y ago
  What were these traps? I'd like to know.
  - ErrantX 17y ago
    - chasing an irrelevant point (the interviewer specifically wanted to move on. NEVER stop that, that is the one single that can cost you a job). - assuming importance (his tone suggests he thinks he knew more than the interviewer. I imagine that might have come across in the interview) - assuming ingorance (if it seems amazing the interviewer is clueless on something then it probably isnt true. Adjust appropriately.) - chasing the wrong issue (if an interviewer needs to draw an answer out - even in a fluid way like that - it will be a black mark on your notes) - assuming irrelevance (his opening remarks suggest he though the question was not relevant to the interview he was having, which suggests he possibly did not treat it with the same gravity. Everything is relevant - the more off the wall the question the more important your answer is). There are more but those were the key points I picked up: not being there and only having his side of that short portion I cant say 100% he fell into every one. But it definitely looks that way :) This is based on similar traps I set up for our interviewee's.
    - byrneseyeview 17y ago
      chasing an irrelevant point Anecdotally, when a one-hour interview turns into a three-hour discussion of a side point, it is a really good sign. If the interviewer isn't into it, give up -- but people who can bounce ideas off of each other tend to come up with more ideas.

badger7 17y ago

One definition of arrogance is "making undue claims in an overbearing manner". You know, like turning "never having heard of" into "not having instant recall of every single CS algorithm".

wglb 17y ago

Attitude is good, but it seems misdirected. For example, are you really sure that the 10,000 frequency list is going to be all that different day to day? While I like to hire people smarter than I am, I rather like to draw that conclusion myself, rather than have somebody try to wrestle me to the ground to prove it.

huhtenberg 17y ago
The attitude was actually quite bad considering this was an interview and not a lazy chat between two colleagues. This guy plainly failed to demonstrate that he can understand the context of the question, which was not an offer to ramble about the question not making much practical sense.