Problem Detail: I want to know the difference between these three languages and it would be great if you would give some examples as well, thank you. 🙂 Asked By : hackhan Answered By : Yuval Filmus An alphabet $Sigma$ is a finite Read More …
Category: Uncategorized
[Solved]: Can you have a binary search tree with O(logn + M) property for the following case
Problem Detail: Let $n$ be the number of strings which are sorted in lexicographical order and stored in a balanced binary search tree. You are provided with a prefix $x$ of which $M$ strings have the prefix $x$. I have devised Read More …
[Solved]: Algorithm exercise
Problem Detail: making exercises to prepare a test I’m having problems to understand 2 questions, the questions are: how many are the leafs of a decisional tree associated to any algorithm for the search problem in a ordered set? for this Read More …
[Solved]: Why does SAT not reduce to QBF?
Problem Detail: So, I remember the professor saying that SAT does not reduce to QBF (Quantifier Boolean Formula) $QBF ::= prop|-QBF|(QBFoQBF)|exists pQBF |forall pQBF$ So, I guess this is not NP, since solving a QBF could grow exponentially. However, $P subseteq Read More …
[Solved]: Independent set on cubic triangle-free graphs
Problem Detail: I know that maximum independent set on cubic triangle-free graphs is NP-complete. Is it still NP-complete in case we require the independent set to be of size exactly $|V|/2$? Basiclly, YES instance of independent set problem on cubic triangle-free Read More …
[Solved]: NP Completeness of 3-SAT problem
Problem Detail: I have started reading on algorithmic complexity for my thesis work. Already have studied on Polynomial time reducibility, NP-Complete, NP-Hard. Now trying to prove NP completeness of some of the classical problems. I have started with 3-SAT problem. 3-SAT Read More …
[Solved]: Equivalence of two context free grammars [for the given example]
Problem Detail: I know that in general it is undecidable whether two context free grammars generate the same language, but I have to do this exercise and I am finding myself somewhat stuck: G1: S->e|aB|bA B->bS|aBB A->aS|bAA G2: S->e|aSb|bSa|SS I tried Read More …
[Solved]: Is it possible to always construct a hamiltonian path on a tournament graph by sorting?
Problem Detail: Is it possible to always construct a hamiltonian path on a tournament graph $G=(V,E)$ by sorting (using any sorting algorithm) with the following total order: $qquad displaystyle a leq b iff (a,b) in E lor left(exists, c in V. Read More …
[Solved]: Binomial coefficient to approach multi-way choices DP problem?
Problem Detail: I’m trying to understand this dynamic programming related problem, adapted from Kleinberg’s Algorithm Design book. Not homework: i’ve already a solution, just considering if i’m ok with the theory. Suppose we want to replicate a file over a collection Read More …
[Solved]: What does up arrow ($uparrow$) mean in pseudocode?
Problem Detail: I’m learning vantage point trees, and I met this while reading the paper Data Structures and Algorithms for Nearest Neighbor Search in General Metric Spaces by Peter Yianilos (Proceedings of SODA 1993, SIAM, pages 311–321; PDF). The following pseudocode Read More …
