The Great Interview Process

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I just wrapped up my 4th and final interview for microsoft for the full time position. There are mixed thoughts on the position in general but the interview process was kind of fun.

There were some personal introspection questions, how you'd fit in the company, why you want to work here, what your weaknesses are, etc. That didn't interest me much and I think I did fine in them. I was really looking forward to the famous microsoft puzzle/coding questions. So I thought I'd share them with the world (or my tiny slice of it).

The coding challenge was sort of interesting. Implement FindString. First time was just determine if a string exists in another string when both strings are treated as arrays of characters. Then part b was determine how many times the first one appears in the second. I had one "off by one" error that was quick to fix and was very close to how the internal workings of find string really work so that went well. The guy interviewing was pretty cool.

Now the brain teasers!

1) You have a 7 foot long bar of gold. I'm going to work for you for 7 days and at the end of every day you pay me one unit of gold. You can cut your bar of gold only twice however, and each cut is a straight line (no spirals). How do you do this?

2) Three men are standing in a line such that the last man can see the two in front of him, the middle fellow can see only the man in the front and the guy in front can't see anything. A woman with a bag of 2 black hats and three white hats comes along, mixes up the hats, and places one randomly on the top of the three men's heads. She then asks last man if he knows what color hat he has on, he says no. She then asks the middle fellow, he says no. Finally she asks the man in front and he says Yes. How does he know what color hat he's wearing?

3) You have 12 sticks laid out at right angles to form four boxes as follows:

 _ _



Moving exactly and only 3 of the sticks, having none remaining and none doubled up, rearrange the sticks such that only three boxes are formed, all of equal size and all of the same size as they are now.

Nothing like filling a glass canyon with an infinte amount of rope or anything, but pretty good puzzles. The stick one was the most challenging for me oddly since spacial reasoning was what I used to kick butt at.

Man I'm such a nerd :)


So? Where's the answer key?

Post your guess and I'll tell you if you're right :)

okay, so all last night I kept waking up with the gold question. Today I thought I had it figured out. No such luck. Please put me out of my misery soon.

Okay, answer key. 1) You cut the bar into a length of 1, 2 and 4. after the first day you give me one. on the second day you give me the 2 and I give you the 1 back. on the third day you give me the one again (I now have three). Fourth you give me the 4 and I give the 1 & 2 back. etc. It's binary counting. 2) The only way the man in the back couldknow what hat he had was if the two in front were both wearing black hats (since he would have one of the white ones left). Since he doesn't know then he has to have seen either a white and a black or two whites. The guy in the middle knows this but he doesn't know what he has. That means he doesn't see a black hat (a black hat would mean he was wearing white). So the guy in the front must be wearing a white hat. he knows this. 3) Like so: _ |_|_ _|_||_|

Wow. Thank you. Sleep at last. {I never would have figured these out.} Decidedly un-nerdy mom.

Man, Zack, I don't envy you the interview process. Brutal. Was this a take home quiz, or was there a proctor standing over you with a stop-watch and a bullhorn? So, uh, even though I'm technically ahead in the nerd points standings at work, my brain wouldn't let itself answer these. I could feel the solutions in there, some lone nerdy neuron raising its hand and shouting "OOO, me, me, me!!", but it was quickly beat up by a gang of neurons whose job it is to register my love of monster trucks.

I think the fact that you are able to relate conversations your neurons have ups your nerdity points :)

The conjugation of the word "nerd" to form other nouns, adjectives, and possibly adverbs also adds to said points.

Okay, the first one was hard, until I finally realized you could ask the guy for change each day. The hat one was probably easier for me becuase i've heard a similar puzzle in the past -- you know, the one with the long line of dwarves where the wizard kills each dwarf that doesn't guess what color hat it's wearing.

wow, that's a decidedly more brutal version of the hat question :)

My head just exploded reading this entry. Which makes typing this rather difficult.

Ahh, thanks... Like Moni, I enjoy these problems, but my brain rarely lets me answer them... I would have just said "uhh..." in the interview... ;)

ouch, my head hurts now....thanks for the answer key!


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