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In order to help you with that, we have compiled a list of questions that are of general nature and have answers that should apply in a variety of situations. Please take the time to browse through those relevant to your question; chances are that we already have you covered. If not, it is likely that one of two things has happend:
You don't understand the reference material.
In this case, the best response is to do further research. That includes picking up textbooks (the reference answers may list some) and asking focused questions on the main site.You understand the material, but you can not apply it to your situation.
In this case, edit your old question to include your attempts at solving the problem and why they failed. Then flag it for reopening; with this new information, we can help you identify your specific problem and move forward.
Remember: "I don't understand any of this, please explain in plain English!" is a bad enquiry. Nobody can know what your problem really is, which factoid would help you understand, and what the required scope for a good answer is. Try instead to phrase questions like "In above proof, why does B follow from A?" or "I have an algorithm but it seems to be wrong for corner case X, how can I fix it?"
That said, you find links to the reference posts grouped by topic below:
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4$\begingroup$ In order to keep this question as clean as possible, I'll protect it. If you think discussion is necessary, please open new thread and/or visit us in Computer Science Chat, where I'll also accept nominations for new/other reference questions. $\endgroup$Raphael– Raphael Mod2013年02月18日 09:08:42 +00:00Commented Feb 18, 2013 at 9:08
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$\begingroup$ See here for a discussion about which questions are suited to become reference questions, and whether we should use a tag to label them. $\endgroup$Raphael– Raphael Mod2013年09月10日 22:23:15 +00:00Commented Sep 10, 2013 at 22:23
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$\begingroup$ see also what is computer science $\endgroup$vzn– vzn2014年06月24日 02:19:12 +00:00Commented Jun 24, 2014 at 2:19
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$\begingroup$ this question collects many popular/standard CS refs $\endgroup$vzn– vzn2014年06月27日 16:36:24 +00:00Commented Jun 27, 2014 at 16:36
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$\begingroup$ Should this include machine models, say, RAM & Turing? $\endgroup$greybeard– greybeard2016年02月17日 07:40:14 +00:00Commented Feb 17, 2016 at 7:40
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$\begingroup$ @greybeard With which (types of) questions? (Please come to Computer Science Chat for discussing this.) $\endgroup$Raphael– Raphael Mod2016年02月17日 11:09:04 +00:00Commented Feb 17, 2016 at 11:09
8 Answers 8
Formal Languages
- What is the difference between an algorithm, a language and a problem?
- Are there other ways to describe formal languages other than grammars?
- How to show that L = L(G)?
- How to prove that a language is not regular?
- How to prove a language is regular?
- What's wrong with my pumping lemma proof? (You must show that every partition $w=xyz$ fails, not just one.)
- How to convert finite automata to regular expressions?
- How to prove that a language is not context-free?
- How to prove that a language is context-free?
- Language theoretic comparison of LL and LR grammars
Complexity Theory
- What is the difference between an algorithm, a language and a problem?
- How can we assume that basic operations on numbers take constant time?
- What is the definition of $P,ドル $NP,ドル $NP$-complete and $NP$-hard?
- Optimization version of decision problems
Decision problems vs "real" problems that aren't yes-or-no - What are common techniques for reducing problems to each other?
- How not to solve P=NP?
- Dealing with intractability: NP-complete problems
- Why nondeterminism?
Algorithms
- What is the difference between an algorithm, a language and a problem?
- Is there a system behind the magic of algorithm analysis?
- How to come up with the runtime of algorithms?
- Explaining the relevance of asymptotic complexity of algorithms to practice of designing algorithms
Justification for neglecting constants in Big O - How do O and Ω relate to worst and best case?
- How can we assume that basic operations on numbers take constant time?
- Differences and relationships between randomized and nondeterministic algorithms?
Asymptotics
- What does the "big O complexity" of a function mean?
- How does one know which notation of time complexity analysis to use?
- Sorting functions by asymptotic growth
(Also: Algorithmic intuition for logarithmic complexity) - Solving or approximating recurrence relations for sequences of numbers
- How do O and Ω relate to worst and best case?
Computability
- What is the difference between an algorithm, a language and a problem?
- Why nondeterminism?
- Are there minimum criteria for a programming language being Turing complete?
- How to show that a function is not computable?
- What are common techniques for reducing problems to each other?
- Differences and relationships between randomized and nondeterministic algorithms?
Operating Systems
We need some filler text until we have more questions or SE will automatically delete the answer.
Architecture
Mathematics
- How do I write a proof using induction on the length of the input string?
Provides a general introduction to induction. - Solving or approximating recurrence relations for sequences of numbers