The software development final exam: Algorithms and Data Structures • Hacker News Board

Re: The software development final exam: Algorithms and Data Structures

#201

Post by rhizome » Tue, Oct 09, 2012, 9:37 PM UTC

tsycho wrote: post #172

SCdF wrote: post #171

I'm not going to put judgement on this statement, but here is (what I'm fairly sure is) the truth: most people developing software (we're talking, not in silicon valley, or in the united states, but globally) need exactly none of this. My current day job is working for the company that maintains and manages NZ's Company registry, as well as a dozen or so other registries over varying subjects. My previous day jobs we…

I used to think so too, and yet... - My current team created a project that lets you run complicated, multi-dependency Java code in an non-blocking manner. Internally, the framework uses topological sorting of a graph of nodes, where each node is a method with potentially blocking code and the dependencies between the nodes are the edges of the graph. The framework is able to set up callbacks automatically in the rig…

Forgive me from asking from ignorance, but isn't the first point begging the question of complicated, multi-dependency code?

Re: The software development final exam: Algorithms and Data Structures

#202

Post by tmoertel » Tue, Oct 09, 2012, 10:50 PM UTC

cperciva wrote: post #49

crntaylor wrote: post #45

Earlier quoted context omitted.

The first two questions I knew the answer immediately because I've read about asymptotics and runtime analysis. Questions 3 and 4 I simply don't have the background (I've never heard of a B-tree, and I've heard of heap sort but I don't know the algorithm). Question 5 I'd not seen before, but an algorithm was quite obvious because I've taken a course on graph theory (of course, my answer could easily be wrong). My ten…

So, my tentative positions is that these questions are easy if you've covered the relevant material before, and very hard to impossible if not. There's a lot of people who are very confidently giving wrong answers to questions, which weighs against that position.

That's interesting. I would expect you not to get many submissions from people who would expect themselves to do poorly on your exam. But, if it turns out that a sizable portion of people who expect to do well do not, that's indeed interesting.

Given the selection bias we would expect among respondents, have you thought about how you will interpret the responses?

Re: The software development final exam: Algorithms and Data Structures

#203

Post by Locke1689 » Wed, Oct 10, 2012, 6:04 AM UTC

rhizome wrote: post #200

Locke1689 wrote: post #195

Earlier quoted context omitted.

Any n-dimensional grid (sometimes called a "Manhattan space") is a bipartite graph. You may find it useful that no odd-length cycles can exist in such a graph.

What is a practical scenario for odd-length cycles in a grid?

Ah, sorry, the odd-length cycle was supposed to be a hint for Colin's problem, not an actual use of bipartite graphs.

I find all the uses of bipartite graphs to be in maximal matching or similar situations.

Re: The software development final exam: Algorithms and Data Structures

#204

Post by pjmlp » Wed, Oct 10, 2012, 6:10 AM UTC

icebraining wrote: post #145

pjmlp wrote: post #35

Earlier quoted context omitted.

Because any professional worth of its salt is supposed to be able to work with googling.

But the author specifically asked people not to "cheat".

Typo. I meant to say "without"

Re: The software development final exam: Algorithms and Data Structures

#205

Post by rhizome » Wed, Oct 10, 2012, 7:27 AM UTC

Locke1689 wrote: post #203

rhizome wrote: post #200

Earlier quoted context omitted.

What is a practical scenario for odd-length cycles in a grid?

Ah, sorry, the odd-length cycle was supposed to be a hint for Colin's problem, not an actual use of bipartite graphs. I find all the uses of bipartite graphs to be in maximal matching or similar situations.

Still..."scenario."

Re: The software development final exam: Algorithms and Data Structures

#206

Post by jemfinch » Wed, Oct 10, 2012, 10:41 PM UTC

xentronium wrote: post #198

jemfinch wrote: post #167

Earlier quoted context omitted.

Your post is largely a straw man and contains snark that certainly does not raise the level of this conversation. I'm talking about passion for programming . I'm not "claiming to own the definition of passion," I'm saying that passion for programming manifests in knowing the answers to questions like Colin's. It simply does.

> contains snark that certainly does not raise the level of this conversation Calling people that don't agree with you mediocre or apologists of mediocrity is just rude.

I did nothing of the sort.

Re: The software development final exam: Algorithms and Data Structures

#207

Post by Locke1689 » Thu, Oct 11, 2012, 3:56 AM UTC

rhizome wrote: post #205

Locke1689 wrote: post #203

Earlier quoted context omitted.

Ah, sorry, the odd-length cycle was supposed to be a hint for Colin's problem, not an actual use of bipartite graphs. I find all the uses of bipartite graphs to be in maximal matching or similar situations.

Still..."scenario."

There are many reasons why you would want a maximal matching. In my case I was working on a distributed system prototype that needed to match block requests my users to cache servers. This is a maximal matching from cache servers who have these blocks available to users requesting blocks.

Re: The software development final exam: Algorithms and Data Structures

#208

Post by eru » Wed, Oct 17, 2012, 12:51 PM UTC

kamaal wrote: post #186

lifeformed wrote: post #164

Earlier quoted context omitted.

I don't know these answers off the top of my head, but if I needed to know them in the real world, I could easily find them out in a couple of seconds or minutes with Google and Wikipedia. The difference between me and someone who is unfamiliar with computer science (but is still good with Google) is that I can read the answers and their corresponding articles and understand what they mean, as opposed to the other pe…

Actually a few years into the industry, I would doubt any body who claims to know these things straight out of this heart(Unless that is his day job). Seriously do people remember all this math all the years they are building software? Unless you spend a great deal of time revisiting these concepts every other month, there is no way this is all going to be in your head. And if you actually are spending that amount of…

Those questions strike me as very basic knowledge. Why would I need to revise constantly to keep that in mind?

And yes, you are right, you can get away without knowing that stuff, and still do awesome work. And you can know all those things, and never get anything done.