4 ms·

It just means making 1 - 2 -- 4 -- 5 - 3 --7 into 7 - 3 -- 1 [union] 5 - 2 -- 1 [union] 4 - 2 -- 1 as one graph. I must say I'm surprised som

It just means making 1 - 2 -- 4 -- 5 - 3 --7 into 7 - 3 -- 1 [union] 5 - 2 -- 1 [union] 4 - 2 -- 1 as one graph. I must say I'm surprised someone can't write this given enough time and proudly claim "they didn't hire me because I couldn't do this". Seems like CS 101 hw.

ghaff 8y ago
As he says, he wasn't a CS major. I can totally relate. I had a pretty popular DOS shareware back in the day (along with some other things). But I wasn't a CS major and would not have been able to answer most algorithmic CS questions unless I had specifically studied them for the purpose of an interview.
- gnulinux 8y ago
  Fine, but don't you think companies should have some filter to choose candidates? In my company I interview often, and most candidates don't know how to code. Asking CS hw questions is a signal that predicts if they can code or not. If you're not a CS major it's ok but in general if you can't figure this question in 15 mins I don't want you to push code to my codebase. Some level of competence is ok. And I don't even work in a FAANG this is a random no name startup in Boston.
  - hinkley 8y ago
    There's one particular category of question that I've started building up a question set in, in part because the last few coworkers who weren't nearly as useful as you would hope all struggled with it: Data transformation. Most of us are at least partly in the business of data transformation. Few of us should be implementing trees (you want coworkers who are informed consumers of data structures, not people who think reimplementing solved problems at work is a reasonable or even sane thing to do). The simplest one I have is this: Hand them a data structure containing a list of lists, have them generate a list of the grandchildren ordered by some property of the grandchild. Like take a list of cars or computers grouped by make and model and give me all of the models sorted by price, or by popularity. If that's too simple, filter by another criteria and do a little data cleanup. I've seen people drop elements, get the order wrong, scope variables too broadly and confuse themselves into grabbing data from a previous iteration, or forget to grab it entirely. And this is exactly the sort of thing that puts your team on the spot for having dumb bugs in production. Not inverting binary trees, or fizzbuzz.
hinkley 8y ago
Reversing a tree (max element on the left) is absolutely CS homework (though probably 201). I'm sure I had to do that at least once or twice. But you can also avoid that most of the time by writing a second in-order traversal algorithm that runs from right to left. But why would I need a data structure where I have the elements by the leaves instead of the roots? Make the nodes doubly linked (parent element) and you get the same effect without all the grandstanding.

ghaff 8y ago

As he says, he wasn't a CS major. I can totally relate. I had a pretty popular DOS shareware back in the day (along with some other things). But I wasn't a CS major and would not have been able to answer most algorithmic CS questions unless I had specifically studied them for the purpose of an interview.

gnulinux 8y ago
Fine, but don't you think companies should have some filter to choose candidates? In my company I interview often, and most candidates don't know how to code. Asking CS hw questions is a signal that predicts if they can code or not. If you're not a CS major it's ok but in general if you can't figure this question in 15 mins I don't want you to push code to my codebase. Some level of competence is ok. And I don't even work in a FAANG this is a random no name startup in Boston.
- hinkley 8y ago
  There's one particular category of question that I've started building up a question set in, in part because the last few coworkers who weren't nearly as useful as you would hope all struggled with it: Data transformation. Most of us are at least partly in the business of data transformation. Few of us should be implementing trees (you want coworkers who are informed consumers of data structures, not people who think reimplementing solved problems at work is a reasonable or even sane thing to do). The simplest one I have is this: Hand them a data structure containing a list of lists, have them generate a list of the grandchildren ordered by some property of the grandchild. Like take a list of cars or computers grouped by make and model and give me all of the models sorted by price, or by popularity. If that's too simple, filter by another criteria and do a little data cleanup. I've seen people drop elements, get the order wrong, scope variables too broadly and confuse themselves into grabbing data from a previous iteration, or forget to grab it entirely. And this is exactly the sort of thing that puts your team on the spot for having dumb bugs in production. Not inverting binary trees, or fizzbuzz.

hinkley 8y ago

Reversing a tree (max element on the left) is absolutely CS homework (though probably 201). I'm sure I had to do that at least once or twice. But you can also avoid that most of the time by writing a second in-order traversal algorithm that runs from right to left. But why would I need a data structure where I have the elements by the leaves instead of the roots? Make the nodes doubly linked (parent element) and you get the same effect without all the grandstanding.