Problem Detail: In the gas station problem we are given $n$ cities ${ 0, ldots, n-1 }$ and roads between them. Each road has length and each city defines price of the fuel. One unit of road costs one unit of Read More …
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CPU frequency per year
Problem Detail: I know that since ~2004, Moore’s law stopped working for CPU clock speed. I’m looking for a graph showing this, but am unable to find it: most charts out there show the transistor count or the capacity per year. Read More …
Perfect matching in a graph and complete matching in bipartite graph
Problem Detail: When I google for complete matching, first link points to perfect matching on wolfram. It defines perfect matching as follows: A perfect matching of a graph is a matching (i.e., an independent edge set) in which every vertex of Read More …
Could the Halting Problem be “resolved” by escaping to a higher-level description of computation?
Problem Detail: I’ve recently heard an interesting analogy which states that Turing’s proof of the undecidability of the halting problem is very similar to Russell’s barber paradox. So I got to wonder: mathematicians did eventually manage to make set theory consistent Read More …
What is the difference between quantum TM and nondetermistic TM?
Problem Detail: I was going through the discussion on the question How to define quantum-turing-machines? and I feel that quantum TM and nondetermistic TM are one and the same. The answers to the other question do not touch on that. Are Read More …
Logic gates from everyday materials
Problem Detail: Logic gates are an abstract device which can be implemented with electromagnetic relays, vacuum tubes, or transistors. These implemenations have been successful in computing in part because of various properties of chainability, durability, and size beyond their basic binary Read More …
What is the difference between an algorithm, a language and a problem?
Problem Detail: It seems that on this site, people will often correct others for confusing “algorithms” and “problems.” What are the difference between these? How do I know when I should be considering algorithms and considering problems? And how do these Read More …
Fixed point, what does it mean in the world of computer science
Problem Detail: I keep coming across references to fixed point in questions and answers at stackexchange and I look up the meaning on the web obviously finding reference at sites such as Wikipedia. However none of the references really answer my Read More …
Cost in time of constructing and running an NFA vs DFA for a given regex
Problem Detail: Repost from Stack Overflow: I’m going through past exams and keep coming across questions that I can’t find an answer for in textbooks or on google, so any help would be much appreciated. The question I’m having problems with Read More …
Why does heapsort run in $Theta(n log n)$ instead of $Theta(n^2 log n)$ time?
Problem Detail: I am reading section 6.4 on Heapsort algorithm in CLRS, page 160. HEAPSORT(A) 1 BUILD-MAX-HEAP(A) 2 for i to A.length downto 2 3 exchange A[i] with A[i] 4 A.heap-size = A.heap-size-1 5 MAX-HEAPIFY(A,1) Why is the running time, according Read More …
