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If Richard Feynman applied for a job at Microsoft (2002)

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Re: If Richard Feynman applied for a job at Microsoft (2002)

#211

Post by rdtwo »

okareaman wrote: post #75

How many ping pong balls would it take to fill a 747? Why do you ask? What problem are you trying to solve? We want to understand your thought process I'd think it was stupid to fill a 747 with ping pong balls and think about something else

This could be a mass or a volume problem, actually there are some other things that could limit the problem statement but those are the obvious ones. But the problem is too general to solve. It really just depends on what you want to do with the ping pong balls and the airplane after you filled the airplane. That’s the critical piece of information that’s missing that should be provided. Otherwise you end up with a bunch of solutions that technically meet the problem parameters but don’t actually solve a real problem

Re: If Richard Feynman applied for a job at Microsoft (2002)

#212

Post by rdtwo »

tharkun__ wrote: post #199
swiley wrote: post #113

Earlier quoted context omitted.

Yeah, unfortunately you get asked to do some pretty silly stuff all the time and being able to cope with that is a critical skill.

Actually I find this a fun thought experiment that can show if you are just a code monkey or a software developer. Let's say the answer is that it's still supposed to fly (working software you are adding a feature to), so also no stuffing ping pong balls into wings and such. Ignore fire hazards and such (no edge cases for now, build an MVP). Now a plane fuselage is basically a cylinder. At one end I assume full size…

Actually the Anwser is simple to solve at least estimate fairly accurately if you assume the Airplane has to fly. You just need to know the model and how many pallets fit into the cargo. The pallets are square with known volumes you pack them at the packing factor for spheres and you are done. There is some bulk cargo area but it’s not big so you need to account for that and That’s about it. You can ignore mass unless the problem lets you smash then then you are just packing plastic blocks into a container and you have to double check you aren’t limited by cargo capacity and range.

A more interesting problem would be to suppose you needed to float a 747 that crashed and sank in tact. How would you go about calculating the right number of ping pong balls to do that.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#213

Post by watwut »

dekhn wrote: post #124
watwut wrote: post #36

Earlier quoted context omitted.

Many manholes are in fact squared. So the premise itself is wrong.

Let's just say there are many questions that people ask in interviews where they have a scientific sounding answer that is simple and wrong (when considered in full context). it's not your job to consider it in full context and give the globally true answer (as feynmann attempted here). it's your job to be cleverer than the interview, perceive what they want to hear, and tell it back to them in a way that maximizes t…

This has nothing to do with full context and some obscure scientific fact. The squared manholes are super common. Many of them are squared and I probably stepped over some squared on my way to interview.

It is like asking why milk is sold always in yellow box. The question makes no sense, because milk boxes can have any color.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#214

Post by dang »

jbluepolarbear wrote: post #180
serverholic wrote: post #176

Earlier quoted context omitted.

Please show me where anyone in this thread is glorifying anything close to sexism.

You have poor reading comprehension. Glorying him and his personality includes his sexist personality as well.

Personal attacks will get you banned here. Please don't cross into name-calling or ideological warfare either. We're trying for something else on this site!

If you wouldn't mind reviewing https://news.ycombinator.com/newsguidelines.html and taking the intended spirit of the site more to heart, we'd be grateful.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#215

Post by [deleted] »

13of40 wrote: post #32
zepolen wrote: post #18

Earlier quoted context omitted.

So what's not serious about that question assuming it was for a programming position?

The answer to that question is the volume of the building minus some factor (let's say 40%) for other stuff like walls and floors, etc. times the number of tennis balls you can fit in a given space, like a cubic meter. Basically... x * y * z * 0.6 * n If you could quickly express it like that, despite not actually coming up with a number, you would probably pass. To me, being able to estimate the scope of things befo…

[deleted]

Re: If Richard Feynman applied for a job at Microsoft (2002)

#216

Post by [deleted] »

david_allison wrote: post #67
jimmaswell wrote: post #35

Earlier quoted context omitted.

Does anything beat just pressing the buttons in order?

Yes. rot13: Bcgvzny fgengrtl vf gb fryrpg "enaqbz", gura vs lbh trg n Crcfv, fryrpg "Crcfv". Gjb cerffrf znk Nsgre fryrpgvat "Enaqbz": * lbh trg n Pbxr (1 cerff) * Lbh trg n Crcfv Vs lbh trg n Crcfv, lbh xabj gung "enaqbz" vf gur ohggba juvpu nyjnlf cebqhprf n "Crcfv" (bayl "Crcfv" be "Enaqbz" pna cebqhpr n Crcfv, naq lbh xabj gur ynoryf ner jebat). Sebz urer, lbh xabj gung gur ohggba ynoryyrq "Pbxr" pna'g cebqhpr n…

[deleted]

Re: If Richard Feynman applied for a job at Microsoft (2002)

#217

Post by tome »

david_allison wrote: post #67
jimmaswell wrote: post #35

Earlier quoted context omitted.

Does anything beat just pressing the buttons in order?

Yes. rot13: Bcgvzny fgengrtl vf gb fryrpg "enaqbz", gura vs lbh trg n Crcfv, fryrpg "Crcfv". Gjb cerffrf znk Nsgre fryrpgvat "Enaqbz": * lbh trg n Pbxr (1 cerff) * Lbh trg n Crcfv Vs lbh trg n Crcfv, lbh xabj gung "enaqbz" vf gur ohggba juvpu nyjnlf cebqhprf n "Crcfv" (bayl "Crcfv" be "Enaqbz" pna cebqhpr n Crcfv, naq lbh xabj gur ynoryf ner jebat). Sebz urer, lbh xabj gung gur ohggba ynoryyrq "Pbxr" pna'g cebqhpr n…

See https://news.ycombinator.com/item?id=27933080 for a better strategy.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#218

Post by vanusa »

conjecTech wrote: post #143
okareaman wrote: post #75

How many ping pong balls would it take to fill a 747? Why do you ask? What problem are you trying to solve? We want to understand your thought process I'd think it was stupid to fill a 747 with ping pong balls and think about something else

I don't get the derision for these kinds of problems. And I think it's unlikely Feynman would have found this unhelpful. These are commonly referred to as Fermi problems. Fermi was a physicist of Feynman's generation - they were probably standing together at Trinity when Fermi did the famous yield approximation. The other physicists held this ability in such esteem they gave it a name and remembered him for it. The q…

The question is meant to gauge whether you can create a simple model of a system that is completely foreign to you, but for which you are familiar with the fundamental rules governing it.

Then talk about a real problem, for chrissake.

You're forgetting that you're "interviewing" someone who not only cranked out supercritical calculations for the first atomic bombs - but the first working models for path integral calculus in QM, and so much other stuff.

And you're asking him about... ping pong balls and 747s?

Granted, your average dev doesn't get to do work quite as interesting as what Feynmann did. But still, if they're senior-level - and especially if they're at least reasonably good - then there's a 99 percent chance they can easily whip out 5 or 10 "end-to-end" problems that they've solved for which the guts were much, much meatier than those of...

Any of these jerk off problems that it used to be almost de riguer for interviewers to ask, a few years back.

Fortunately this practice is starting to fade from popularity, but unfortunately, not quite fast enough.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#219

Post by tharkun__ »

rdtwo wrote: post #212
tharkun__ wrote: post #199

Earlier quoted context omitted.

Actually I find this a fun thought experiment that can show if you are just a code monkey or a software developer. Let's say the answer is that it's still supposed to fly (working software you are adding a feature to), so also no stuffing ping pong balls into wings and such. Ignore fire hazards and such (no edge cases for now, build an MVP). Now a plane fuselage is basically a cylinder. At one end I assume full size…

Actually the Anwser is simple to solve at least estimate fairly accurately if you assume the Airplane has to fly. You just need to know the model and how many pallets fit into the cargo. The pallets are square with known volumes you pack them at the packing factor for spheres and you are done. There is some bulk cargo area but it’s not big so you need to account for that and That’s about it. You can ignore mass unles…

Square pallets sounds awesomely easy indeed. I didn't know that existed. I've only seen the ones that are wider on the top vs. the bottom. Like this one https://www.dsm.com/content/dam/dsm/dyneema/en_GB/images/app...

Those look like they'd be easier to deal with too though. And in any case a great discussion in the interview can ensue regardless. Which is the point.

Interesting second problem too. So you have a regular 747 you say, which I suppose has a mass I can look up somewhere, we have statistics probably about how much cargo and passenger baggage usually weigh (or maybe these are even available for the specific flight?) and passengers hopefully made it out alive since you said the aircraft was intact and didn't burst into pieces.

Now would come the part of just looking stuff up that I don't know but know is known to man already so you better look it up instead of reinventing it all. Apparently from a quick google I would probably want to know how much the plane's buoyancy already works for us (it definitely sank so there's that, but did it barely sink or did it sink like a stone?) and see how much a ping pong ball wants to float. My guess is that the ping pong balls are so buoyant that we can even ignore their small plastic shell and calculate it as if the plane was directly attached to the needed volume of air to make it float.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#220

Post by hungryforcodes »

JadeNB wrote: post #181
goodcanadian wrote: post #80

Earlier quoted context omitted.

Well, I think it gets it wrong when it comes to the safety issue question. Something being possible, even if unlikely, is obviously more dangerous than something being impossible. Feynman would definitely understand that even if he insisted that the main reason for the shape of the cover is the shape of the hole (which is probably true). EDIT: Assuming Feynman is deliberately being obtuse, he might point out that, wh…

> Something being possible, even if unlikely, is obviously more dangerous than something being impossible. Feynman would definitely understand that even if he insisted that the main reason for the shape of the cover is the shape of the hole (which is probably true). This is a very good point for someone who is known, among other things, for his O-ring demonstration ( https://en.wikipedia.org/wiki/Rogers_Commission_Re…

Love the o-ring story. One of the reasons he's my hero.
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