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Problem Detail: It’s possible to parse a document using a single pass from a state machine. What is the benefit of having two passes, ie. having a lexer to convert text to tokens, and having a parser to test production rules Read More …

Problem Detail: Is there already modified version of selection sort that works like this pseudocode: a // the array, index starts at 1 (not zero-based) n = len(a) for x in 1 to n big = x small = x last Read More …

Problem Detail: I am stuck and having a hard time with this question. I want to construct a CFG for the language $$L = {{a^lb^mc^n | l,min N, n=|l-m|}}$$ I know that the language consists of strings where: 1. number of Read More …

Problem Detail: There is a family of random graphs $G(n, p)$ with $n$ nodes (due to Gilbert). Each possible edge is independently inserted into $G(n, p)$ with probability $p$. Let $X_k$ be the number of cliques of size $k$ in $G(n, Read More …

Problem Detail: Consider the problem: Given an undirected graph and two of its vertices, is there a path between them? I often read that this problem can be solved in linear time in the number of vertices! I am not sure Read More …

Problem Detail: The state space is decribed with 3 boolean variables $p,q$ and $r$ (so we have 8 states total). We have an action, let’s say $a$. Action $a$ can be executed when $p=text{False}$ and $q=text{True}$ and the result is $p=text{True}$, Read More …

Problem Detail: I have recently learned about various randomized algorithms for load balancing. The model is always that there are $m$ balls and $n$ bins and the balls arrive one at a time. The task is to minimize the maximum load Read More …

Problem Detail: I’m trying to understand reduction, this is from my textbook and is not a homework problem or even any exercise, just trying to understand an example they present. This is the reduction they give: PROOF We let R be Read More …