IgnouGroup Social Campus
Problem Detail: I’m working on a simple project of software engineering that should combine two patterns. I choose Abstract Factory and Decorator patterns to modify (dynamically) objects created with the concrete Factory classes. My question is: is delegating object decorations to Read More …
Problem Detail: e.g. $xy+x+y=x+y(x+1)$ ? The expressions are from ordinary high-school algebra, but restricted to arithmetic addition and multiplication (e.g. $2+2=4; 2.3=6$), with no inverses, subtraction or division. Letters are variables. If it helps, we can forbid any expression representable with Read More …
Problem Detail: I’m trying to reduce an optimization problem to a decision problem, more specifically, consider the Max-Cut problem in its decision version: Given $(G=(V,E),k)$ as input, where $G$ is an undirected weighted graph (all weights are positive integers, formally: $w: Read More …
Problem Detail: I was fooling around with Google Blocky’s Maze demo, and remembered the old rule that if you want to solve a maze, just keep your left hand to the wall. This works for any simple-connected maze and can be Read More …
Problem Detail: It is proven by Time hierarchy theorem that EXPTIME-complete do not belong to P even if we do not know if NP belong to P. Before I read wiki, I found EXPTIME algorithm for solving 3-sat, the brute algorithm Read More …
Problem Detail: Given weighted directed graph $G = (V,E,w)$, where $w : E to mathbb R^+$ source vertex $v in V$ vertex subset $U subset V$ how to find a shortest directed path from $v$ containing all vertices from $U$? Note Read More …
Problem Detail: Let $Sigma$ be some finite set of characters of fixed size. Let $alpha$ be some string over $Sigma$. We say that a nonempty substring $beta$ of $alpha$ is a repeat if $beta = gamma gamma$ for some string $gamma$. Read More …
Problem Detail: Given $n$ arrays of size $k$ each, we want to show that at least $Omega(nk log k)$ comparisons are needed to sort all arrays (indepentent of each other). My proof is a simple modification of the decision tree argument Read More …
Problem Detail: The following example was given in an online lecture I was watching. A phone directory is 1000 pages long, and we have to find the name “Zurich Smith”. The algorithm is as follows: Split the phone directory into half. Read More …
Problem Detail: My question here is dealing with the residual that I get. We are trying to prove $T(n) = 3T(n/3) + n$ is $O(n*log n)$. So where I get is $T(n) le cn[log n – log 3] + n$. So Read More …
