1. I apologize if the question is not formed well, I tried my best.
  2. "Only" means anything else is discarded.
  3. A stupid man’s report of what a clever man says can never be accurate, because he unconsciously translates what he hears into something he can understand. (You are the clever man here, so please try to be simple with me)
  4. Please Answer an atomic question; If your advice contains a lot of difference advice, please list them.
  5. Please make your answer practical (i.e., in terms of "Do" & "Don't")



What is the (Point of reference) or (Milestone) or (factor) that I only should use when I decide "I understand algorithms"?

Example for "Milestone" Indicator

If you watched a video on how to do derive x2; if you finished the video and failed to obtain the derivative, you will ask yourself intuitively "did I really understand the video?". (The end of the video) is the (Milestone) in case of Mathematics.

And this is my question, what is the milestone in case of Algorithms?


  1. Am I required to only learn popular algorithms & their solution patterns?
  2. Or is it like Mathematics? (I should learn "how to derive an algorithm and its complexities" (even if I will not be able to derive the optimal solution) but at least, I can identify, understand & build an algorithm even if I never encountered it.

All Understanding-Factors that I know

  1. I can only solve the homework provided by the instructor.
  2. I can only implement the algorithm in any programming language? or implement & identify also the written algorithm and its complexity? ("write" or "read & write")
  3. Should I be able to identify an implemented code's algorithm even if I did not study it before? if yes, then how?

Question's Reasons & Explanation


Algorithms courses (explicitly MIT 2011 & 2020, Stanford, San Diego, Princeton) teach only "The Algorithms only written in the book", thus, you cannot identify/understand anything beyond what they taught in the course.

Reasons Explanation

This is similar to learning the test instead of the subject, you only can answer questions, already taught to you, and get good grades without actually learning the subject or how to use it in the real world.

Resulting Problem

Unfortunately, I could not decide how to study Algorithms till now because:

  1. I do not know how to identify if I am actually learning or just deceiving myself, which will be used to choose the course that I will learn from.
  2. I am certain that you can get the delusion of knowing algorithms very well just because "you got a good grade" or "applied it once before".


These are the answers that I reached so far, but I cannot verify because I lack the experience:

  1. Learn by practice, specifically, problem solving.
    Reason: because you do not need to learn everything at once, just learn what you need and let the calculation & invention for scientists and researchers.
  2. Understanding-Factor is the ability to identifying the class of problems & their solutions when you encounter a problem. If you failed, search for new theorems that solve that problem. But you always need to know how to calculate the space & time complexity of the theorem. (I still do not know how to calculate the complexity of the algorithm).
    Reasons: (same as the above reason)
  3. Only study the test (provided algorithms).
    Reasons: Because 90% of the Business problems require only already implemented & tested algorithms; Thus, your only role is to choose "what" & "when" to use an algorithm. The other 10% is left for researchers (via enhancement or even creation). Even if you are in the Algorithms development, you need tools that include a big number of Algorithms Design Techniques & A lot of Applications on it to be able to enhance & test it.
    Issue: I found some questions/answers in the community that contradicts that "90% & 10%" which are: What do I need to know about algorithms?, How do I know if my algorithm is right (without coding)?, How to fool the "try some test cases" heuristic: Algorithms that appear correct, but are actually incorrect.
  4. Learn Algorithms & Data Structures and also Design & analysis of Algorithms & Data Structures.
    Reason: Because it is not enough to know some Algorithms patterns but to also understand & analyse it (the person gave examples that I will translate in case somebody cares).
  5. Algorithms are not a simple thing that can be covered within a single course. It can be broken down into the following:
    a. Algorithm Design (which explains the general algorithm concept).
    b. Algorithm Proof.
    c. Algorithm Analysis.
    d. Algorithm Standard Application.
    e. Algorithm Enhancement & Addition.
    f. Practical Application of Algorithm.
    Each & every point is a course/topic in itself, and there can't be a course that covers all topics at once; Not even the most popular books (CLRS).
    Therefore, the 3 questions of understanding an algorithm is composed of three main aspects (design, analysis, application). So as a conclusion, you do not need a single course to cover algorithms but rather multiple courses until you get it.
    So to rephrase your question, "Is algorithms branch a (principle & skills type science branch) or (pattern science branch whereby you only apply patterns)?" and the answer is: I think it is both, you apply patterns but also whenever you need to dig deep, you really need to have the principle & skills that enable you to find a pattern.
    Another aspect is, how to study algorithms?
    a. Solve it on paper in a mathematical form.
    b. Draw flowcharts.
    c. watch other people's answers (solution and analysis).
  • 3
    $\begingroup$ There is no central authority that is requiring you to do anything nor is there a definition of "someone understanding algorithms". Instead, why not just decide yourself? Learn and apply whatever you find interesting. If you want to measure your knowledge by doing exercises or taking tests, that's also fine. Finally, let me also suggest reading about the imposter syndrome. $\endgroup$
    – Juho
    Commented Mar 2, 2022 at 20:51
  • $\begingroup$ @Juho I know about impostor syndrome, to be fair, i still did not get deep into algo; I want to work as a SE and I should fit for it (hence, there is some authority that is requiring me to have some standard knowledge). Finally, I cannot decide by myself because to answer my own question i need to have certain knowledge, that if i already had it, I wouldn't have asked the question :) $\endgroup$ Commented Mar 2, 2022 at 21:07
  • 2
    $\begingroup$ So suppose you decide that you "know algorithms". Does that mean you can't make mistakes, are not allowed to forget details or must declare you can't study more? I wouldn't worry so much. In my experience, software engineers don't care or need algorithmic skills much, things like software design, domain understanding etc are more important. $\endgroup$
    – Juho
    Commented Mar 3, 2022 at 5:51
  • 1
    $\begingroup$ I have been doing practical algorithmics for about forty years now. I only scratched the surface. $\endgroup$
    – user16034
    Commented Mar 3, 2022 at 8:51
  • 1
    $\begingroup$ And sorry to say, gossip less and practice more. $\endgroup$
    – user16034
    Commented Mar 3, 2022 at 8:52

1 Answer 1


The premise of the question is faulty. There is no point at which "I understand algorithms" -- it is not a black-and-white matter, where one day we are required to say "I don't understand algorithms" and then I learn one more fact and the next day I am allowed to say "I understand algorithms". Instead, it is a matter of shades of grey.

My advice: don't get caught up in trying to answer a global question like "can I say I understand algorithms?". Instead, learn whatever topics you find interesting or useful. There is always more to learn.

  • $\begingroup$ I think I am misunderstood. Let me give an example that further facilitates explanation, If I Understand "Integration by parts" then that means, at the very least, that I know how to apply it if I am told to do so, and I am an expert if I know when to use it without an external source. What I am asking here is the same, a point of reference; would "solving the homework" be enough as a point of reference to answer the question "do i know algorithms?"? I am sorry if it is still not simply explained & I understand your answer (that my questions is a wrong question as it holds fake facts). $\endgroup$ Commented Mar 2, 2022 at 21:57
  • 1
    $\begingroup$ @OmarShawky, I think I understood your question. I'm sticking with my answer. The question "do I know algorithms?" is not answerable as that's not how things work. $\endgroup$
    – D.W.
    Commented Mar 2, 2022 at 22:43

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