Chat transcript from TCHS SRM 60: Spotlight Session with John Dethridge
Handle	Comment
John Dethridge	g'day
jmpld40	Hi John, thanks for coming
John Dethridge	no problem Jessie :)
binarywithme	hii sir
msg555	good day!
ortschun	hi!
binarywithme	John Dethridge: hii sir
binarywithme	John Dethridge: u r welcome here
John Dethridge	binarywithme: thanks
rooparam	welcome sir
binarywithme	John Dethridge: sir tell us something about you in brief.
John Dethridge	I'm a mathematician, currently working as a computer programmer, because I seem to be good at programming. :)
binarywithme	John Dethridge: r u studying right now or not?
John Dethridge	binarywithme: I'm working at Google now
NilayVaish	john Dethridge: Which university did you study at?
John Dethridge	Melbourne University
rooparam	sir what do u mean by "I retire"
John Dethridge	rooparam: oh that was a joke... I changed my quote to "I retire" after I won the championship. :)
ortschun	John Dethridge: when did you start programming ?
John Dethridge	ortschun: I started programming when I was 8, with basic on an Apple 2
irancoldfusion	John Dethridge: Which Google office?
John Dethridge	irancoldfusion: Mountain View, California
viclei	John Dethridge: Hi John! You did very successfully in the ACM. What was your preparation like?
John Dethridge	viclei: I mostly did problems from previous ACMs. For about a month before the final my team would get together and solve previous regional contests and world finals
John Dethridge	viclei: for my first year at least... in my second year at the ACM finals I didn't train that much
ortschun	John Dethridge: is 17 too late to start practicing for being a topcoder?
John Dethridge	ortschun: it's never too late really if you're going to put the time into it. A lot of successful topcoders started late, although usually they were strong mathematicians already, which helps a lot
binarywithme	John Dethridge: sir if i will peform well in programming will the google give me job?
John Dethridge	binarywithme: they might, you should apply and find out!
superkinhluan	John Dethridge: you're not working now?
John Dethridge	superkinhluan: I'm working at Google
superkinhluan	John Dethridge: I know you are working at Google, but you are not working right now?
John Dethridge	superkinhluan: oh I see. No not right now, I'm taking a break! :) Although I have a bunch of programs running on our clusters, so I'm waiting for those to finish anyway.
L	:P
L	http://googlified.com/googlers-excuse-for-slacking-off/
John Dethridge	L: exactly!
zdravko_b	John Dethridge: hi john, i am a masters student, but I can still learn something from you ;)
John Dethridge	zdravko_b: hi
FameofLight	John Dethridge: How long you are coding
John Dethridge	FameofLight: I started when I was 8, although I didn't do all that much coding when I was at school... I concentrated more on mathematics
binarywithme	John Dethridge: sir how much pratice n level should needed to reach at google.
John Dethridge	binarywithme: well, I guess a good minimum to get a job as a software engineer is to finish a college course on software engineering, and get some experience while you're doing it
hallan_cs	john Dethridge: I have a brother with 10 years old, I should teach him a programming language?
John Dethridge	hallan_cs: sure, if he's interested :) I think a good way to start is to use a simple language and write a number of programs. Something like basic. Some people recommend python.
tharis	hallan_cs: no doubt
tharis	hallan_cs: Python FTW <- the best language in the world :)
Phicardo	tharis: after c
tharis	Phicardo: Not! :p Python's great for everything! C's great for speed!
Phicardo	tharis: 0k, after Java xDD
tharis	Phicardo: Fanboy! :p :D
Phicardo	tharis: :P
John Dethridge	Someone PM'd me a question about what areas of maths are useful in computer science... I think combinatorics and graph theory are the main areas. But any area with lots of proofs is useful as well, to develop skills in logical thinking.
FameofLight	John Dethridge: Exactly How you define balance between Practice and Algorithm Study , If you weak theory background
John Dethridge	FameofLight: I think the best way to figure out that balance is to figure out the skill level you're targetting... the stuff you need to learn to get onto your university's ACM team is going to be different to what you need to do well in a TCO...
John Dethridge	FameofLight: so you should figure out what algorithms you want to know well, maybe by choosing chapters from a textbook, and then try to solve a lot of problems using those techniques
FameofLight	John Dethridge: Not for ACM Team , Not for TCO , just to have good passion in algorithms
John Dethridge	FameofLight: I guess if you were interested in algorithms, but not necessarily for competitions, then you could spend more time reading papers and less time coding
John Dethridge	FameofLight: A lot of academics do that... they have a broad knowledge of algorithms but probably couldn't sit down and code them very fast
FameofLight	John Dethridge: Thanks for Suggestion , I am little good in Mathematics at School , (Also success is motivation) so in college I started with Programming , being not good it feel bad
martins256	John Dethridge: what math books you suggest for new computer scientists?
John Dethridge	martins256: maybe get some entry-level graph theory books. Maths competition problem sets, at a level you can solve, might be a good idea too
viclei	John Dethridge: What are some good team strategies for ACM?
John Dethridge	viclei: I think good team strategy depends on the relative strengths of your team. For example if you have a very fast coder on easy problems, let him start on one right away.
John Dethridge	viclei: If someone is good at tougher problems, have them read and think about the harder problems away from the keyboard
John Dethridge	viclei: knowing when to swap people away from the keyboard can be tough. It's also a good idea for the two people not typing to sync up on what they're working on
John Dethridge	viclei: so that you each have a better picture of where the team is on each problem
binarywithme	John Dethridge: sir how much hard world ifnal problmes are?
John Dethridge	binarywithme: the acm world finals (if that's what you mean) have been getting harder... there are often 2 or 3 tough problems when in previous years there might have only been 1
yiuyuho	John Dethridge: John, what makes you so good at this?
John Dethridge	yiuyuho: I think having a strong mathematics background helps a lot. Most of the top-ranked coders on TC do.
rooparam	John Dethridge: i want to read Knuth, but it's maths makes me think like i have wasted my schooldays .... what should i do now ?
Sarkin	john Dethridge: I have CLRs but I'm having difficulties reading it because of the math what do you suggest?
Sarkin	Which books will help?
John Dethridge	I guess if the math in CS textbooks is beyond what you know, you should go back and do more math... get high school or college freshman algebra textbooks
John Dethridge	you rarely will need much calculus
ortschun	John Dethridge: what was the most exciting moment for you in all competitions you've joined
John Dethridge	ortschun: I guess challenge phase is the most exciting, in any TCO/TCCC final that's been close. :)
John Dethridge	ortschun: also the last few minutes of coding phase, when you're not sure who will finish the problems they're working on...
tharis	john Dethridge: what was your age when you: started programming, won your first match/competition?
John Dethridge	tharis: I started at 8, but I was doing more mathematics than coding during school. The first programming competition I won was some national school-level competition.
John Dethridge	tharis: There was an international contest I could have gone to that followed from that, but it conflicted with the IMO so I didn't go
binarywithme	John Dethridge: whould u plz give ur code of world final problems .so i can get some help
John Dethridge	binarywithme: you can read my code from past TCOs on the topcoder website.
John Dethridge	But some people might suggest that my code is not the clearest to learn from. :)
Larry	some?
myprasanna	fi fj :)
John Dethridge	Larry: yeah, some. "almost everyone" counts as "some" :)
Tavo92	John Dethridge: John, are you better at maths or at programming? What is the difference between a person that is good in math and the one that is good in programming?
John Dethridge	Tavo92: I consider myself a mathematician, but on ranking I think I'm far better as a programmer. :) I think a math background helps once you get to much harder problems.
viclei	John Dethridge: Will you be coming to Australia anytime soon? :D
John Dethridge	viclei: probably :) I was in Sydney for the GCJ regional final there.
viclei	John Dethridge: Oh, wish I could have gone :( hehe
vexorian	John Dethridge: Did you "retire :)" ?
John Dethridge	vexorian: not really :) I am training less than I used to though. Perhaps semi-retired. :)
armansuleimenov	John Dethridge: what would you suggest to concentrate on when preparing to TCO as opposed to ACM regionals?
John Dethridge	armansuleimenov: The TCO is harder than ACM regionals generally. I would do the practice rooms in the applet, especially rounds from previous TCOs.
John Dethridge	armansuleimenov: Then go to other online judge sites.
ortschun	John Dethridge: do you check others results while you're coding? and have you ever felt that you're not gonna make that problem?
John Dethridge	ortschun: yeah I do check the scoreboard pretty often. Especially when other people are solving in a different order. Then you get some information on how hard the other problems are.
wack-a-mole	John Dethridge: What else do you do apart from coding?
John Dethridge	wack-a-mole: What else do I do? I play a lot of other games. :) Computer games, card games, board games, etc.
nicolodavis	John Dethridge: How many hours a day did you spend practising when you were working your way up, and what did you do?
John Dethridge	nicolodavis: in the weeks before my first TCO, I spent about 3 or 4 hours a day coding. Mostly solving past problems.
John Dethridge	nicolodavis: maybe a bit more than that
nicolodavis	John Dethridge: ok
afonseca	John Dethridge: Do you think that a man (20 years) can learn math for programming in like 6 months?
John Dethridge	afonseca: well you can certainly learn enough, but more is better :)
afonseca	John Dethridge: hehe, that motivates me :)
skaterdude69	John Dethridge: Did you get your PHD in Comp Sci.? I remember on CNN you said you were thinking about it.
John Dethridge	skaterdude69: nope, I left college and joined Google
Giorgi	John Dethridge: I agree with you, I know a lot of algorithms , but I can't solve hard problems wich needs deeply mathematical knowledge, what would you advice, study math from beggining?
John Dethridge	Giorgi: well, when I say math is important, it's not just that some hard problems use math. Usually the amount of mathematics you need to know for the actual problem is not that much, maybe a little geometry or number theory.
John Dethridge	Giorgi: It's more that the skills you get in doing mathematics help in CS also.
John Dethridge	Giorgi: but yes I would go back and do high school math if you need to, especially algebra and geometry.
Giorgi	John Dethridge: ok thanks
Quelloquialism	John Dethridge: Have you ever considered changing your name to "John Liferidge" to promote optimism?
skaterdude69	Quelloquialism: LOL
tharis	Quelloquialism: ROFL
John Dethridge	Quelloquialism: I'll tell you what, I'll consider that seriously and get back to you. :P
srikanth_sg	any nice material for learning stl?
srikanth_sg	suggest me please
John Dethridge	srikanth_sg: I used http://www.sgi.com/tech/stl
wack-a-mole	John Dethridge: What IDE and OS do you use?
John Dethridge	wack-a-mole: for TopCoder, I just use the in-applet editor
vexorian	John Dethridge: Considering you code like that, and you use no plugins or IDE, how do you manage to debug your code?
John Dethridge	vexorian: I try not to have bugs. Otherwise, I put in printfs to see what's going on.
vexorian	Are those provisions like not using plugins/IDE some sort of technique to avoid solving the problem very fast since people would think you are cheating?
John Dethridge	vexorian: some people do use IDEs, I just prefer not to.
Tavo92	John Dethridge: Do you think that it is "easier" to be a good coder in countries such as Poland, Russia, USA? Or it is having a good mentor or finding the right material?
John Dethridge	Tavo92: I think if you're self-motivated and have internet access, you have the same chance anywhere
zdravko_b	John Dethridge: is academia less fun than google?
John Dethridge	zdravko_b: hmmm there are parts of academia I would not enjoy, but you would perhaps have more freedom in what you worked on
zdravko_b	John Dethridge: what exactly in academia don't you like (excluding payment ;) )
John Dethridge	zdravko_b: paperwork, applying for funding. I can't really speak that authoritatively on it though, I've never been an academic.
Sarkin	john Dethridge: If you started that early I think you participated in the IOI? if yes what medal did you get?
John Dethridge	Sarkin: Australia didn't participate in the IOI yet when I was in school. We do now though. I taught at a couple of our training schools. :)
vlad_D	John Dethridge: yeah, but you have gold in ACM
John Dethridge	vlad_D: yes
zdravko_b	John Dethridge: is your work at google creative :) ?
John Dethridge	zdravko_b: sure, there's a lot of room for creativity when your goal is broad
John Dethridge	zdravko_b: say you want to improve the relevance of search results, for example... there's a lot of scope for trying different algorithms to do that
zdravko_b	John Dethridge: i see
Tavo92	John Dethridge: Why do you work at Google?
John Dethridge	Tavo92: I think Google has a lot of interesting problems to work on, and great people
John Dethridge	Tavo92: and a fun environment
Tavo92	John Dethridge: But, in google you don't face "ACM-like" or "TC-like" problems, do you?
John Dethridge	Tavo92: yes we often do. Graph theory, DP, geometry, it's all relevant
ortschun	John Dethridge: there's a rumor that google asks algorithm problems in their interviews is that right? :)
John Dethridge	ortschun: absolutely. We want people who are good at algorithms.
John Dethridge	ortschun: One of the most famous is how you sort a million phone numbers with only 2MB of ram, and variations on that
tharis	john Dethridge: sort 1kk nrs with 2MB of RAM? how?
John Dethridge	tharis: that's what you have to figure out :)
tharis	john Dethridge: LOL I'm only 16... When I'm 30, I'll PM you with the answer, ok?
John Dethridge	tharis: you can be more ambitious than that :)
tharis	john Dethridge: I am! I'm looking for the Nobel! :) Coding and IOI are only hobbies! ;)
wack-a-mole	John Dethridge: Is it true that Google has a firefighters' slippery pole for when you are hungry?
Tavo92	wack-a-mole: Is that a joke xD ?
wack-a-mole	Tavo92: I saw it in an email :)
vexorian	John_Dethridge: and is the pole really for when you are hungry, or for something else?
zdravko_b	wack-a-mole: i've seen pictures, in zurich i think :)
John Dethridge	wack-a-mole: yes I think the Zurich office has that :)
zdravko_b	John Dethridge: which google are you at?
John Dethridge	zdravko_b: Mountain View, California
geekru2	John Dethridge: do you solve puzzles and mathematical problems? does it help iproving coding skills?
John Dethridge	geekru2: yes, I look at problems from the IMO and related contests pretty regularly
viclei	John Dethridge: So do companies like Google look for algorithmic ability for a practical purpose or more for distinguishing good problem solvers?
John Dethridge	viclei: Both. We do want employees who are strong in algorithms, and I think it's also a good way to assess problem-solving ability. That's my opinion anyway.
Blue_Ant	John Dethridge: Hello
John Dethridge	Blue_Ant: hi
FameofLight	John Dethridge: How important is code on paper for Topcoder
John Dethridge	FameofLight: not very. I often scribble diagrams while I'm thinking, but I wouldn't ever write code.
rajeshsr	John Dethridge: You participated at acm-icpc?
John Dethridge	rajeshsr: yes, I went to the world finals in '00 and '01
iit2007106	which language do u hthink would be better?
John Dethridge	iit2007106: I prefer C++. For a first language when learning to program, something simple like basic.
gowrav	john Dethridge: is it worth making myself good in C++ .. i am really hardworking on that but compnies like google use python .. m i right ??
gowrav	john Dethridge: what is best to master C++ or python as per googlist
John Dethridge	gowrav: C++ is more useful than python I would say.
snguyen	John Dethridge: private quesion, you can ignore : How old are you, JD? :)
John Dethridge	snguyen: 22. :)
zdravko_b	John Dethridge: 22, wow, so young :)
John Dethridge	zdravko_b: I lied. :)
ortschun	John Dethridge: wow. and what about internship? do you have to be a top coder t be intern in Software Engineering department
John Dethridge	ortschun: we have a lot of interns who are CS students with good grades.
geekru2	John Dethridge: what is a good coder..one who knows a lot of algos? or one who can create algos on spot during contests?
John Dethridge	geekru2: both of those are important. You need to know a lot of algorithms, but even more importantly to get to the top you need to be able to adapt them or come up with new algorithms on the spot to solve problems
John Dethridge	geekru2: most final rounds avoid problems that can be solved just by one standard algorithm.
Tavo92	John Dethridge: Is it more important to have good grades or to have competed succesfully in algorithm competitions?
John Dethridge	Tavo92: well, whenever you're applying for a job somewhere, they're going to consider everything. I think non-college achievements like success in competitions are a good way to distinguish yourself from other people who also have high grades.
rajeshsr	John Dethridge: Can u share, how u practised for that?
John Dethridge	rajeshsr: I mostly practise by doing previous contest problems
pdallago	John Dethridge: How do you keep improving your mathematical and algorithmic skills nowadays?
John Dethridge	pdallago: I keep solving more problems to improve. Although I haven't been practising that much recently, apart from test-solving all of the GCJ problems. :)
gowrav	john Dethridge: whats is the most usefull language for criticle solutions! (this might change my world)
John Dethridge	gowrav: C++
theexpository	John Dethridge: Is there an algorithmic paradigm that you consider the most fundamental?
John Dethridge	theexpository: not really, I think you need knowledge in a broad range.
Soyoja	John Dethridge: How about your record in World finals '00 and '01?
John Dethridge	Soyoja: in ACM '00 we came second, or something, they had a bit of a screwup with the judging. In '01 much worse.
vexorian	John Dethridge: Why do you think top contest coders tend to like C/++ so much?
John Dethridge	vexorian: I think more top coders prefer C++ because of the low-level control that's available.
glue2glee	John Dethridge: what did you study at university? Math or CS ?
John Dethridge	I did both.
deusemx	John Dethridge: do you think perl has been replaced by ruby and python?
John Dethridge	deusmx: I don't really have an opinion on perl and python and ruby. :)
Quelloquialism	John Dethridge: So I once lost a programming contest due to a small bug in my implementation of BFS, and ever since then I've hated coding BFS. Are there any algorithms you have a similar strong hatred for?
vexorian	Quelloquialism: Do you use dijkstra for simple BFS problems since then?
Quelloquialism	vexorian: No, I just grudgingly code BFS... =)
John Dethridge	Quelloquialism: you should practise BFS more. :) I don't really have a dislike for any particular algorithm.
John Dethridge	Quelloquialism: Computational geometry problems can be annoying when they have lots of special cases, but that's the same for everyone, not a special hatred I have for them. :)
viclei	John Dethridge: Thanks for the responses. Any chance you can come back to Melbourne to coach my team for the ACM finals? :P
John Dethridge	viclei: I probably won't be back for that long. Good luck though.
viclei	John Dethridge: Haha. Thanks :) Hope you can come come in to MU if you're around the area.
gowrav	john Dethridge: what should b learned now .. crossplatform or linux or windows as a good start
binarywithme	John Dethridge: linux is better thnx windows what u think ?froma programmer's point of view
John Dethridge	I wouldn't worry too much about what OS you use
Larry	John Dethridge: what do you do, practice-wise, about problems that you can't figure out the solution, but know that they exist?
John Dethridge	Larry: I try harder until I get it. :)
theexpository	John Dethridge: Is there a particular source/book that you prefer for solving geometry/probability/maze problems?
John Dethridge	theexpository: no not really. I learn mostly by solving problems.
Tavo92	John Dethridge: What is your favorite food before a contest :) ?
John Dethridge	Tavo92: I usually have coffee and chocolate before competitions. :)
theexpository	John Dethridge: Topcoder problems vs acm regional problems?
John Dethridge	theexpository: I think it's more important to do problems at the right level for what you're training for, rather than which contest they're from
Hamed	John Dethridge: Why did you retire? :)
John Dethridge	Hamed: I didn't really retire, it was a joke. :) I do practise less now though.
samshu	**samshu hopes it is an easy SRM
vexorian	**vexorian hopes the SRM is easy for him but no one else.
samshu	vexorian: hehe
rooparam	best of luck to all for coming SRM
rooparam	thanks for ur time sir
ortschun	John Dethridge: thank you so much for today :)
Blue_Ant	John Dethridge: See you
snguyen	thx a lot JD, wish u the best!
ortschun	John Dethridge: thank you so much for today :)
ortschun	again:)
ortschun	John Dethridge: bye
rajeshsr	John Dethridge: Thanks u. Bye
John Dethridge	np :)