ignougroup, Author at IgnouGroup

How to prove that a language is not regular?

January 12, 2017March 15, 2018 ignougroup

Question Detail: We learned about the class of regular languages $mathrm{REG}$. It is characterised by any one concept among regular expressions, finite automata and left-linear grammars, so it is easy to show that a given language is regular. How do I Read More …

What is the definition of P, NP, NP-complete and NP-hard?

January 12, 2017 ignougroup

Question Detail: I’m in a course about computing and complexity, and am unable to understand what these terms mean. All I know is that NP is a subset of NP-complete, which is a subset of NP-hard, but I have no idea Read More …

How to calculate the number of tag, index and offset bits of different caches?

January 12, 2017March 15, 2018 ignougroup

Question Detail: Specifically: 1) A direct-mapped cache with 4096 blocks/lines in which each block has 8 32-bit words. How many bits are needed for the tag and index fields, assuming a 32-bit address? 2) Same question as 1) but for fully Read More …

How to convert finite automata to regular expressions?

January 12, 2017March 15, 2018 ignougroup

Question Detail: Converting regular expressions into (minimal) NFA that accept the same language is easy with standard algorithms, e.g. Thompson’s algorithm. The other direction seems to be more tedious, though, and sometimes the resulting expressions are messy. What algorithms are there Read More …

What is a the fastest sorting algorithm for an array of integers?

January 12, 2017March 15, 2018 ignougroup

Question Detail: I have come across many sorting algorithms during my high school studies. However, I never know which is the fastest (for a random array of integers). So my questions are: Which is the fastest currently known sorting algorithm? Theoretically, Read More …

Why is quicksort better than other sorting algorithms in practice?

January 12, 2017March 15, 2018 ignougroup

Question Detail: In a standard algorithms course we are taught that quicksort is $O(n log n)$ on average and $O(n^2)$ in the worst case. At the same time, other sorting algorithms are studied which are $O(n log n)$ in the worst Read More …