Problem Detail: Some confusion about time-complexity and A*. According to A* Wiki the time-complexity is exponential in the depth of the solution (shortest path): The time complexity of A* depends on the heuristic. In the worst case of an unbounded search Read More …
Category: Uncategorized
[Solved]: Let A,B be languages. If A is decidable and B undecidable, then A reducible to B
Problem Detail: So I’m learning for an upcoming exam and there’s a specific problem which I can’t show: Let A be decidable and B undecidable, then $A le B$ Can someone give me a hint how to solve that? Furthermore, does Read More …
[Solved]: Linear time algorithm for finding $k$ shortest paths from $s$ to $t$
Problem Detail: Definition. Given a graph $G=(V,E)$ and two vertices $s$ and $t$, the $k$-shortest-paths problem is finding the $k$ shortest simple paths between $s$ and $t$ in $G$. Note that the length of these paths is not necessarily equal, Read More …
[Solved]: implementation of queue using stack with REVERSE
Problem Detail: Suppose a stack implementation supports an instruction REVERSE, which reverses the order of elements on the stack, in addition to the PUSH and POP instructions. I’m looking for implementation of queue where ENQUEUE takes a sequence of three Read More …
[Solved]: Examples of processes / problems that cannot be tackled by Turing Machines
Problem Detail: I know that there are problems that cannot be solved by any algorithm, such as the Halting problem. I also know that some processes cannot be even adequately approximated by any Turing Machine (equivalently, any digital computer), meaning that Read More …
[Solved]: Relation between hardware and software
Problem Detail: I’m very interested in computing and programming. I have done a lot of programming with different languages although I have a question nobody was able to answer until now. I question myself how is software related to hardware. to Read More …
[Solved]: How “coplanar” is a set of points?
Problem Detail: Assume that we have 10 points. If all those points are on the same plane, they all are coplanar. But some of them might be at a different place. That disrupts the structure of the plane if we were Read More …
[Solved]: A puzzle in Permutation
Problem Detail: There are two stacks A and B. A : a,b,c,d (‘a’ is on top and ‘d’ is at the bottom of the stack) B : (empty) There are two rules. If an element of A is popped, it must Read More …
[Solved]: Properties of polynomial time many-one reductions
Problem Detail: I’m working on old multiple choice exams and would like to know if the following statements are true or false: a) $L_1 le_p L_2 le_p L_3 Rightarrow L_1 le_p L_3$ b) If $L in mathsf{NP}$ and $U le_p L$ Read More …
[Solved]: Problem with implementing Brzozowski’s algorithm
Problem Detail: I’ve been trying to implement Brzozowski’s algorithm but I’ve just discovered that it creates suboptimal automata for a certain class of inputs, having one more state than what is really needed in the result. I can show it on Read More …
