With time2kill..Come2this blog!

  • sugg: go over and delist
    • t_killTime
    • oq tags
    • t_sticky tags
    • fuxi tags
    • Private posts
    • Draft posts
  • coding: go over github + t_algoClassicProb/t_algoQQ11/t_commonCodingQ22
Advertisements

learn new tech for IV(!!GTD): learn-on-the-job is far from enough

Example — you programmed java for 6+ months, but you scored below 50% on those (basic) java knowledge question I asked you in skype chat. You only know what to study when you attend interviews. Without interviews, you won’t encounter those topics in your projects.

Example — I used SQL for at least 3 years before I joined Goldman Sachs. Until then I used no outer join no self-join no HAVING clause, no CASE, no correlated sub-query, no index tweaking. These topics were lightly used in Goldman but needed in interviews. So without interviews, I wouldn’t not know to pay attention to these topics.

Example — I programming tcp sockets many times. The socket interview questions I got from 2010 to 2016 were fairly basic. When I came to ICE I looked a bit deeper into our socket codebase but didn’t learn anything in particular. Then my interviews started showing me the direction. Among other things, interviewers look for in-depth understanding of

· Blocking/non-blocking

· Fast/slow receivers

· Buffer overflow

· Reliability

· Ack

How the hell can we figure out these are the high-value topics in TCP without interviews? I would say No Way even if I spend 2 years on this job.

[18] IV (!! GTD)body-building logbook by skill

I’d like to keep the table columns simple.

muscle delta when duration intensity
2D coding Q 3->5 2018 2D 3
perm/combo 5->8 2017 4D 3
string/array 6->7 2
backtracking 1->6 2018 2D 3
tail recursion 0->5 2017 x hours 1
big O analysis 7->8 2018 1
sorting algo nlg 7->8 2018 x hours 1
advanced recursion 3->5 2018 x Days 3
whiteboard best practice 6->7 2018 2 days 3
shared mem 2->4 2018 2 H 2 coding experiment
c++ for coding Q 3->8 2017 10-20 D 2 bbg
socket 3->6 17-18 x days 2 thanks to IV, not project
rvr/mv/forward 2->5 16-18 x days 2
noexcept 0->5 2018 1 H 1 Trex IV
other c++11 2->4 1
py basics 4 coding test 3->5 2
FIX?
STL?

spend 4Hr/D self-study@@ #XR

Hi XR,

I called you to highlight to you the realistic amount of hours we can spend on self-study.

Real example 1 —- I monitored it for months in my Master’s program — I would spend about 30 hours a week, including lectures, tutorial classes and homework(about 15-30 Hr/week, often taking up one full weekend-day). If I self-study without the program, I think it will drop to 3 hours a week. Why so low? Read on.

Eg 2 —- Some graduate students prepare for coding interviews by going through some question bank, just as you planned. Could be close to a hundred questions, during a 3M period — just my imagination, not based on any observation. They probably have 4 hours/weekday + 16 hours/weekend-day of free time. How many hours do they actually spend ? I would guess 10 – 20 hours a week. Why so low? Read on

Real example 3 —- In Singapore, I had kids, bills, grocery, household chores, home maintenance, family outing … so I had far less spare time than now, but still I probably had 1H/weekday + 8H/WED (weekend-day) for myself. In reality, I averaged 3 hours a week on self-study, but you know what a motivated person I am. Why so low? Read on

Real example 4 —- in Feb 2018 I had some very promising, valuable interview opportunities (FB). Even on the very last weekend before the interview, my time utilization rate was very very low. I lock myself up in office with no one else to distract me. I sleep only 7 hours and I eat in front my computer. In fact, I tell my friends “I spent entire weekend in office without going out of the building. You would think I could spend 15 hours a day on the preparation. Well, more like 6. Why so low?

It’s not all about motivation. I had high motivation in Singapore. I had the highest motivation over the recent weekend. But the numbers are still much lower than “theoretical limits”. There’s huge difference between wall-clock time vs real time spent:

Example 5 —- My son would spend an hour pretending to study 20 Chinese characters but only learn 3 characters and soon forget all of them. So the real time he spent was … a few minutes?

It’s about intensity. I call it laser energy intensity.

Real example 6 —- in a coding interview, my mind was working at top capacity. Over 15 minutes I solved some very tough problem. The rest of the interview (I was there for 3 hours) was far less intense, though it’s still intense, as intense as any technical interview.

Example 4 continued —- I time myself for white-board coding. Over 20 minutes my mind was working under immense pressure. Over the next 2 hours I sit down at a computer and make the actual code work. It’s still a lot of work, but my mind was at 50% peak capacity.

Use numbers to gauge the amount of workload and your time utilization rate. Say each problem (in homework or a coding exercise) takes average 30 minutes in exam / interview. Beside eating, using toilet, you have 15 hours to spend, so you would want to do 30 problems. How many can you actually complete? Perhaps 6, up to 10. Why so low? Our mind can’t operate at peak capacity for 15 hours!

In Example 4, after I spend 20 intense minutes, I need to wind down. After I spend 2 hours on lower-intensity work, I also need to wind down.

In Example 1, at the lecture/tutorial classes, the intensity was about 30% on average. That’s why I can do 2-3 hours. At a higher intensity the students’ mind would /disengage/ after an hour. All experienced teachers would slow down and give breaks when introducing tough technical topics.

In Example 1, When I spent 10 hours to complete my homework, my intensity was about 50% and I took many breaks. Actually the concentration time spent was more like 6-7 hours.

How does this mental “workload” compare to paid project work in a regular job, including work-from-home?

  • 😦 Project work is often repetitive or mundane. I can’t choose another topic.
  • 🙂 Paid work often has much bigger impact (otherwise why paid) and often a sense of achievement
  • 😦 Paid work stress is harmful, since the impact is high.
  • 🙂 Project work often has a discipline built-in, so we don’t wander off. This is similar to my Master’s program
  • 🙂 Project work requires us to keep going when the going gets tough. Also in my Master’s program

personal learn`]difficult workplace: %%tips #XR

I understand your boss could be pushing hard and you have colleagues around who may notice what you do…. Well, Not much wiggle room for self-study. A few suggestions:

  • try to put some technical ideas into the code. I did manage to put in some threading, some anonymous inner classes, some memcpy(), some local byte array buffer into my project, so I get to practice using them. (I understand the constraints of a tight time line…)
  • it takes a few minutes to write down new findings discovered at work. I put them in my blog. I also try to spend a little more time later on to research on the same topic, until I feel confident enough to talk about it in an interview.
  • I try to identify some colleagues who are willing to discuss technical issues in my project. I try to discuss only when boss is not paying attention. Boss is likely to feel we are taking too much time on some unimportant issue.

If the learning topic is not related to work, then I feel it’s similar to checking personal investment account at work. (In the ICE office now, some employees get a cubicle with 4 walls so they get more freedom than me.) Do your colleagues check their investment accounts at lunch time? I believe they always get a bit of personal time. In GS, on average very roughly 1 out of 9 working hours is spent on personal matters, and the other companies have higher than that. We all need personal time to call insurance, immigration, repair, … The managers might need even more personal time. I would guess at least 60 minutes a day is yours. Question is how to avoid drawing attention. I don’t care that much about drawing attention, so I often print technical articles to read, or read on-line, or blog on-line.

It’s more discrete to write email to record your technical learning. I often send those emails to my blog (email-to-publish) or to my personal email address.


Personal time (be it 60 minutes or 3 hours at some banks) is never enough. We just have to try harder to squeeze a bit more out of the 9 hours. If you are serious about learning in your personal time, then I see two much bigger obstacles
1) family responsibility and distractions
2) insufficient motivation and persistent effort (三天打鱼两天晒网)

In my Singapore years (4.5 years), I felt overwhelmed not by work but family duties, so my weekends/evenings were almost never put to good use for personal learning. I can’t just blame my family members though. I do get quiet time 10.30 pm to 12.30 and many hours on weekends. Somehow, I didn’t put in persistent effort so I didn’t experience significant growth in my technical capabilities.

A very capable colleague was able to do his math research at home and make progress. His wife is probably a full time home maker and takes care of their 3 kids. He is wealthy so he may have a maid and a separate study room at home. However, I feel a more important factor is his persistent effort and focus. A rolling stone gathers no moss. By the way, this same guy runs about 5 miles at least 4 times a week. Determined and efficient. Good time management and correct priorities.

If (a big IF) we are sufficient motivated, we will find time or make time, either the 60 minutes at work, or on trains, or at home, or in Starbucks. In reality, very few individuals have that level of motivation, so I believe some external factors can help, such as (my favorite) —

* jot down some idea in a draft email and do a bit of research whenever I get time to build on the idea, until it’s complete and fairly substantial. Idea could be something I overhead, an idea I’m truly interested in. The learning is mostly in the research but also in the subsequent reviews. If I don’t review the email, I will forget most of it. When I do review it, I not only refresh my memory, but I often discover connections with other things I studied, or find new ideas to learn — 温故而知新. Learning is associative, like growing a spider web.

sense-of-urgency, for kids+professionals #IBM #Alok

If there is no time frame specified, there is no sense of urgency and nothing to measure against. If you set a time frame you will be able to use this as a reason to go back to your boss at regular intervals and update them on the progress, ask for help and set appropriate expectations throughout the year.”

So said an IBM site. “Sense of urgency” is a simple but powerful propaganda slogan introduced by the 1993 incoming CEO of IBM. In my experience, workers with a consistent sense of urgency will be noticed by the boss. A boss without a sense of urgency could be a nice boss but not effective.

I like this slogan, because my son needs it, badly. It should be instilled at a younger age.

If a frog sits in a slow boiler, she won’t have the sense of urgency to jump out.

By default, folks fall into inaction — weight management, regular exercise, or self-improvement. Setting some kind of measurable goal is a simple device. My dad goes a step further — until now, he has daily plans and he gets things done.

Take for example my house search. If I don’t have any sense of urgency, I would simply postpone indefinitely any research or discussion including school-districts. Reality is, sooner or later my son needs a school. The more I postpone my research, the less time I have to do a proper research. So I do feel a sense of urgency, but hopefully I’m not hitting too many colleagues in the office.

Let’s remind each other the sacrifices we made — the cut, living away from family, additional expenses including rent.

[[Focus]] for technical xx

See also my email on “the zone”, the “creative engine”.

As the book author, Dan’s idea of focus is stricter. It’s related to a student’s focus. I told my son he needs better concentration. As a student I was very good with concentration.

Compared to my “traction” days, I now spend too much time emailing, blogging on non-tech, calling home, asking about housing, shopping, food preparation … But that’s not the key. During the work or study hours, I am not focusing as I did in primary school.

Traction days are associated with growth, concentration, positive feedback loop, tech blogging….

I think Yang was the first manager who pointed out I need better focus. Perhaps he meant I tried to study all the systems in PWM Comm all at once. I made real progress (with ErrorMemos, SQL, Java …) after I sent my wife/son back to Singapore.

I made real progress with quant stuff during the Barcap days. However, I also had to keep job hunting remotely.

Avichal, who sat beside me, said I had too many distractions…

I guess the initial code complexity requires focus… Without sufficient focus, the complexity is just too much for my capacity. Better shut out everything else and focus on delivering something non-trivial. Remember PWM, Quartz, …

Grandpa had a lot to say about focus…

##study subjects I enjoyed as student(+professional)

(You don’t have to read this lengthy blog post.)

All my examples below required a long period of persistent effort. My son is unwilling to put in even 30% of my effort, so he wouldn’t find any enjoyment.

After the initial few hours of curiosity, learning any subject was always challenging, boring, or repetitive. The mental workload always wears us down, so we always needed conscious effort to stick to it I.e. stay focused and apply ourselves. The joy comes as a light at end of the tunnel. No exception.

In contrast, watching TV, playing electronic games, eating, sight-seeing, shopping … don’t require any effort. When we get bored with it, we are free to break away — there’s no measurable progress to worry so give-up has absolutely no consequence. We choose to stick to it (say, a game) only because we enjoy it. Therefore no effort required.

If a teenager takes on professional gaming as a paid job, he will invariably find it monotonous, repetitive, uninteresting, dull, tiring, before he can earn any money. Those gamers who do earn money are able to earn money precisely because they put up with the boring stuff — persistent effort.

— Now the study subjects I enjoyed, ranked by amount of effort:

I enjoyed blogging on technical subjects. My QnA interviews directly benefit from my blogging but this is not the biggest reason for the enjoyment. In fact, most of my technical blog content is not required for interviews. I can see my blog improving in quality (and quantity) as I revise and expand each article progressively. Blogging let’s me achieve deeper understanding on many tough topics like sockets, reflection, c++template, move-semantics, quant, complex SQL, … I call it "真本事". I then notice the superficial knowledge in fellow programmers, who studied only 20% of what I read.

I enjoyed memorizing English words, in my teenage years. I developed my own method. I was able to memorize 30 – 100 words a day for a few months (I refresh each word 20 to 40 times spaced out over 6 months). The fast progress was "breathtaking". Self-confidence grew. I actually learned some words my English-educated Singapore classmates didn’t know!

I enjoyed Chinese composition in my secondary Year 2-3, when I found my literary "voice", my style of writing. For about 2 years before that break-through, I was always in the bottom 10% in my class in terms of composition and every assignment was a pain like giving birth to a short, boring baby. The pain, self-despise, self-pity was one of the deepest in my childhood. I felt inadequate almost like crippled. The breakthrough was a liberation. I achieved it by writing daily essays for a few months. My output slowly improved from very dry, simple "流水账" to have some meaning, some color, some personality, some nice expressions. It became creative expression.

(Paradoxically, as a student I was very strong in math/physics, but I never had the same enjoyment as I had learning English and Chinese composition. I think my joy was in overcoming highly visible personal limitations — sense of breakthrough and liberation.)

I enjoyed piano playing after years of repetitive, boring, tough practice. In my life I never again put up with this much practice — 5000 repeated practices x 2 minutes/repetition in some cases.

I know more c++than c#(spent X years full time)

Action: spend enough (30?) hours revisiting my 1000+ cpp (including socket, stream..) blog posts and explore just a little beyond them.

(I blogged about exactly the same observation before …) Here’s a paradox — i spent 2 years in a full time c# job, arguably longer than my full time c++ experience. However, sometimes I feel I understand dotnet less than C++.

Reason? Many aspects of the languages are never used in-depth on work projects, so length of experience != depth of experience. We need spare time self-exploration to learn those aspects like:

– template meta programming
– custom operator new/delete
– memory tuning
– memory leak detection
– threading
– async communications
– pure virtual
– ++i vs i++

(… not a complete list by any measure.) Interviewers are notorious for testing these obscure or advanced, theoretical topics.