Problem Detail: I have read that linear bounded automaton is a Non deterministic Turing machine. Why is it so? Asked By : user5507 Answered By : Yuval Filmus The definition of LBA (for example given in Wikipedia) is a non-deterministic Turing machine which Read More …
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[Solved]: Why do puzzles like Masyu lie in NP?
Problem Detail: The puzzle is made up of (n x n) squares so when taking the problem the input size would be n. Rules of Masyu: The goal is to draw a single continuous non-intersecting loop that properly passes through Read More …
[Solved]: Multiplication in $O(ncdot log n)$
Problem Detail: I was looking in here, and I noticed the best runtime for multiplication of two $n$-bits numbers is $O(ncdot log n cdot 2^{O(log^* n)}$, but I can easily notice an algorithm that runs in $O(ncdot log n)$. After all, Read More …
[Solved]: Use Dijkstra to find negative cycles in a graph
Problem Detail: I will state the problem: Suggest an algorithm that works in $O(|E| + |V|log|V|)$ time that checks if there are negative cycles in a graph. So, I saw the runtime, and I immediately said we need to use Dijsktra’s Read More …
[Solved]: Go Back N ARQ Question
Problem Detail: I am a computer science under graduation student, and was going through some Go Back N ARQ (Computer Networking) videos on YouTube, and got a doubt in a question, which according to me should have a different answer than Read More …
[Solved]: Why don’t nodes carry as many pointers as possible in a skip list?
Problem Detail: From this main picture explaining how skip lists work from Wikipedia, we see that some nodes carry different amounts of pointers to other parts of the list: Wouldn’t it make more sense to have every node carry 4 pointers Read More …
[Solved]: Are there problems that are polynomial-time equivalent to factoring composites?
Problem Detail: It seems that factoring a number known to be composite is in its own interesting little complexity class, e.g. polynomial time using quantum computing even though no one has proved $mathsf{P} = mathsf{NP}$ for quantum computing. Are there interesting, Read More …
[Solved]: Reconstructing a data table from cross-tabulation frequencies
Problem Detail: Say there is a data table $D$ that we cannot see, with $M$ columns. We are given exact cross-tabulation frequencies for all ${M choose 2}$ pairs of columns, that is how often each combination of two values occurs. From Read More …
[Solved]: Does the normal form theorem imply that every partially computabe function is primitive recursive?
Problem Detail: This is Normal Form Theorem (Second Edition of Computability, Complexity, and Languages written by Martin Davis page 75): Let $f(x_1,…,x_n)$ be a partially computable function. Then there is a primitive recursive predicate $R(x_1,…,x_n,y)$ such that: $f(x_1,…,x_n) = L(min R(x_1,…,x_n,z)_z)$ Read More …
[Solved]: Automatically generate meaningful queries for a data table
Problem Detail: My field of research is not Database or AI. But I have some problems to solve, and would like to know which branch this kind of problems belong to, and what are the results. The main question is: given Read More …
