Brilliant, yet simple technical questions, can be used for work interview
Few days ago, a friend of mine, sent me set of demonstration questions for 11th grade computer science students from Russia. I throw eye on this exam and decided to use some of those questions to test candidates in my company for hardware engineer position (we’re looking for). If you’re good candidate for this position, you should be able to answer all those questions without even think a minute.
Following those questions:
Automatic system recoded informational message in Russian from Unicode (16-bit) into KOI-8 (8 bit). After recoding the length of the message decreased by 480 bits. What was the length of the original message in characters?
1) 30 2) 60 3) 120 4) 480
There are 119 participants in bicycle race. Special designed system registers cyclers passing waypoint by writing his serial number with minimum possible number of bits. What will be the size of temporary message, recorded by the system after 70 cyclers passed the waypoint?
1) 70 bits 2) 70 bytes 3) 490 bits 4) 119 bytes
а=D716, b=3318. What the value of c if a<c<b?
1) 11011001 2) 11011100 3) 11010111 4) 11011000
Please calculate 438+5616?
1) 1218 2) 1718 3) 6916 4) 10000012
What logical expression equals to: & !( !B | C ), while &: logical AND, !: logical NOT and |:logical OR
1) !A | !B | !C 2) A & !B & !C 3) A & B & !C 4) A & !B &C
F is a result of logical expression execution with arguments A, B and C
| A | B | C | F |
| 1 | 0 | 0 | 1 |
| 0 | 0 | 0 | 1 |
| 1 | 1 | 1 | 0 |
What is the expression for F?
1) !A & !B & !C 2) A & B & C 3) A | B | C 4) !A | !B | !C
For encoding characters A, B, C and D we decided to use two bits numbers sequence (from 00 to 11). What was the result of coding sequence BACD on base 16?
1) 4A 2) 411 3) BACD 4) 1023
Led table contains of number of leds. Each led can be in one of following states: “On”, “Off”, “Blinking”. What is the minimal number of leds should be on table in order to display 18 difference signals?
Please calculate 2514 + 11-4 – 2110?
To calculator there are only two commands 1: “add 3”, 2: “multiply by 4”. Please write down the sequence of the calculator command in order to convert number 3 to number 57 while using not more, then 6 commands. For example to convert 2 into 50 you should write following: “21211” (X4,+3,X4,+3,+3)
The speed of data transfer over network is 128000 bits/sec. Please calculate the time (in seconds) will take to transfer 625 kBytes in this network.
Write a simple program (by using your favorite programming language) to convert the array of 30 integers into array of modulus of items from input array without using modulus calculation special function.
Good luck!
For people, currently employed in my company (hardware devs) it took less, then10 minutes to solve all those questions. However, I was shocked, that at least half of new candidates, come to interview failed to solve it.
January 30th, 2009 · Comments (19)
19 Responses to “Brilliant, yet simple technical questions, can be used for work interview”
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February 4th, 2009 at 1:41 am
Sorry, but at least two of those questions are just broken.
a < c < b
a = 0xD7 = -41
b = 0×39 = 57
Which means we are talking about 8 bits signed. Which means options become: -39, -36, -41, -40 which in turn means c can be -39, -36 or -40.
Another one:
BACD = 01001011 = 0x4D which is not offered.
February 4th, 2009 at 2:12 am
You right, it should be 331~8, not 33~18. My fault
February 4th, 2009 at 5:04 pm
“For people, currently employed in my company (hardware devs) it took less, then10 minutes to solve all those questions. However, I was shocked, that at least half of new candidates, come to interview failed to solve it.”
“You right, it should be 331~8, not 33~18. My fault”
Should you all be fired!!!!
February 10th, 2009 at 4:54 pm
Before you look down your nose at those who cannot solve your math problems, you should possibly look into the proper use of commas. See corrected quote below. (Only one was corrected as there are way too many grammatical errors on this page to correct.)
“For people currently employed in my company (hardware devs), it took less than 10 minutes to solve all those questions. However, I was shocked that at least half of new candidates who come to interview failed to solve it.”
February 10th, 2009 at 4:56 pm
LOL,
I missed like 3 more errors in your quote. Damn!
February 10th, 2009 at 10:46 pm
Yap. I have some problems with English grammar, but I’m working on it
March 11th, 2009 at 3:45 pm
Solving these questions does not proved anything, except that you did well in theoretical courses. While in school I knew a lot gals that were genius in theoretical stuff, but fail miserable when it come to do higher level programming projects like concurrency,cryptography.
April 6th, 2009 at 12:38 pm
If you were to ask me any of those questions at an interview I would walk out.
The reason why: I’m dyslexic, I struggle to perform mental arithmatic and especially so under pressure.
But being dyslexic doesn’t stop me from being a damn good developer, it just means I have to get better specifications which display the calculations! or alternatively not go down to such a low level, when it’s not necessary.
April 7th, 2009 at 12:28 am
Peter,
All those questions can be asked also verbally and have nothing with mental math.
I’m sure, that you’re a good programmer, however I have two programmers, who have APD and dysgraphia. Me, personally, have phoneticized spelling (as you can see in this blog), but I’m good with it
April 8th, 2009 at 10:03 am
Spoken like someone to whom math comes easily.
q1. Math
q2. Math
q3. Math
….
There is only a few questions there which don’t involve math, written or mental.
The .Net framework hides a lot of math and binary information from the developer.
I find questioning like this to be the equivalent of Red Brick university snobbery.
i.e. if your degree isn’t from a red brick university then it isn’t a true degree.
if you can’t do the math you can’t be a programmer? is a false statement.
I don’t know the mechanics of my car engine but I can use it.
Admittedly if the role is heavily math based then some warning up front would be required on the job posting which would deter the likes of me.
April 17th, 2009 at 8:27 am
question 2: There are 119 participants in bicycle race. Special designed system registers cyclers passing waypoint by writing his serial number with minimum possible number of bits. What will be the size of temporary message, recorded by the system after 70 cyclers passed the waypoint?
best answer is to use a bit mask, one bit per cycler. Your message is always 119 bits.
July 29th, 2009 at 12:40 am
If I was to be given these questions at an interview I’d just walk out.
Such stupid questions, they really are, they prove nothing.
October 24th, 2009 at 11:48 pm
when i was hiring some devs for a networking prj. I asked like
ushort a = 2;
ushort b = 6;
please switch the value of a and b w/o extra variables or memory.(If someone make it, i will ask her/him to consider overflow)
December 1st, 2009 at 12:50 pm
ushort a = 2;
ushort b = 6;
//please switch the value of a and b w/o extra variables or memory.
a = 6;
b = 2;
February 8th, 2010 at 1:04 am
When I had to hire developers I noticed a distinct difference between math geniuses and those who would produce working code with limited time-frames and budget. The latter also used to be more team players than the former.
Therefore, once a quick interview determined wether they were talking about something they actually know, I’d give them a sample application to expand with some new stuff (i.e. a new database based window, some graphing outputs) and I’d see what they’d produce and in what time.
The math geniuses were often still “planning” by the time the others were done.
Of course this won’t work if your company is heavily into astronautic calculations and similar, but so far it’s not been an issue here.
February 8th, 2010 at 6:47 pm
#10… I currently work as a Developer Liaison and mostly handle issues at higher levels of specification and testing.
My personal background in programming forced me to learn Hex, Decimal, and Binary.
Using the Microsoft Calculator in Windows 7, I was easily able to Q1 & Q2. I skipped Q3 because I didn’t understand the difference between the 16′ and 8.
In fact, I didn’t realize that the -4 in “+ 11-4″ meant that it was a signed integer.
That said, I think that companies feel really swell handing out idiotic formulaic tech tests. This is not the way professional work is ever developed. The most reasonable way to get to know someone is not to question them on syntax but to show application of information.
A great example comes from another post on this site regarding OOP programmers who should know “when it should be virtual and when abstract”.
March 1st, 2010 at 4:23 pm
I was trying to get the feed for the RSS for this blog but it is not showing up in Google Chrome. Any suggestions?
April 2nd, 2010 at 10:19 am
I enjoy these little games; my answers:
3, 3, 4, 2, 3, 4, answer not present, 3, 9, 22111, 625/16
May 31st, 2010 at 4:34 pm
hey,this is Heriberto Cernuto,just observed your Post on google and i must say this blog is great.may I share some of the information found in this blog to my local buddies?i am not sure and what you think?anyhow,Thank you!