User Hendrik Jan

59 votes

Minimum spanning tree vs Shortest path

answered Dec 10, 2013 at 10:12

38 votes

Algorithms computing if a number is a multiple of 3

answered Jan 11, 2013 at 21:38

28 votes

Planar regular languages

answered Sep 12, 2019 at 21:59

26 votes

Why are computability problems always written in full caps?

answered Aug 23 at 16:20

24 votes

How to find middle element of linked list in one pass?

answered Apr 20, 2016 at 10:48

22 votes

Can a tree be traversed without recursion, stack, or queue, and just a handful of pointers?

answered Nov 8, 2013 at 22:32

19 votes

Accepted

Languages that satisfy the pumping lemma but aren't regular?

answered Jan 27, 2013 at 0:47

19 votes

Proof that for 2n nodes of +1 and -1 position doesn't count

answered Nov 28, 2021 at 0:18

18 votes

Accepted

Number of possible search paths when searching in BST

answered Apr 5, 2013 at 10:05

15 votes

Accepted

Context-free Languages closed under Reversal

answered Nov 28, 2012 at 15:04

15 votes

Accepted

What does it mean to say that a language is "effectively closed" under an operation?

answered May 9, 2013 at 20:08

15 votes

How to prove that a language is context-free?

answered May 27, 2014 at 23:52

15 votes

How can I generate first n elements of the sequence 3^i * 5^j * 7^k?

answered Feb 23, 2015 at 11:20

15 votes

Given a language L what can we say about the decidability of whether this language is regular or not?

answered Oct 24, 2017 at 14:11

14 votes

Does every data type just boil down to nodes with pointers?

answered Jan 6, 2017 at 23:22

14 votes

Proving the regularity of a certain language

answered Oct 5, 2016 at 1:25

14 votes

Accepted

Is it decidable whether a pushdown automaton recognizes a given regular language?

answered Apr 25, 2015 at 10:32

14 votes

Algorithm to determine whether two regexes are equivalent

answered May 25, 2013 at 20:26

14 votes

What is the difference between finite automata and finite state machines?

answered Mar 7, 2013 at 15:37

14 votes

Accepted

Non-regular language whose prefix language is regular but not the whole set of words

answered Sep 14, 2022 at 12:46

13 votes

What's the difference between a binary search tree and a binary heap?

answered Jun 20, 2014 at 13:54

13 votes

Accepted

Why do we have different algorithm for MST when graphs are directed?

answered Apr 12, 2016 at 17:30

12 votes

Accepted

Example of unrestricted grammar which produces non-context-sensitive language

answered Jan 13, 2017 at 20:40

12 votes

Accepted

Incorrect proof of closure under the star operation using NFA results in the NFA recognizing undesired strings?

answered Oct 31, 2017 at 11:49

12 votes

Accepted

Cases where string concatenation is commutative

answered Sep 1, 2017 at 18:42

12 votes

Accepted

Parikh's Theorem: CFL's "contain" regular languages?

answered Dec 8, 2014 at 1:19

12 votes

Accepted

Why in a min priority queue (heap based) it is called "decrease-key" and not just "set-key"?

answered Jun 2, 2015 at 8:11

12 votes

Why is not known whether integer factorization can be done in polynomial time knowing how to do primality tests efficiently?

answered Dec 15, 2015 at 14:09

12 votes

Accepted

Is search a binary heap operation?

answered Feb 24, 2013 at 10:58

11 votes

Why is NFA minimization a hard problem when DFA minimization is not?

answered Jun 15, 2013 at 18:24

Stack Exchange Network

741 Answers

Minimum spanning tree vs Shortest path

Algorithms computing if a number is a multiple of 3

Planar regular languages

Why are computability problems always written in full caps?

How to find middle element of linked list in one pass?

Can a tree be traversed without recursion, stack, or queue, and just a handful of pointers?

Languages that satisfy the pumping lemma but aren't regular?

Proof that for 2n nodes of +1 and -1 position doesn't count

Number of possible search paths when searching in BST

Context-free Languages closed under Reversal

What does it mean to say that a language is "effectively closed" under an operation?

How to prove that a language is context-free?

How can I generate first n elements of the sequence 3^i * 5^j * 7^k?

Given a language L what can we say about the decidability of whether this language is regular or not?

Does every data type just boil down to nodes with pointers?

Proving the regularity of a certain language

Is it decidable whether a pushdown automaton recognizes a given regular language?

Algorithm to determine whether two regexes are equivalent

What is the difference between finite automata and finite state machines?

Non-regular language whose prefix language is regular but not the whole set of words

What's the difference between a binary search tree and a binary heap?

Why do we have different algorithm for MST when graphs are directed?

Example of unrestricted grammar which produces non-context-sensitive language

Incorrect proof of closure under the star operation using NFA results in the NFA recognizing undesired strings?

Cases where string concatenation is commutative

Parikh's Theorem: CFL's "contain" regular languages?

Why in a min priority queue (heap based) it is called "decrease-key" and not just "set-key"?

Why is not known whether integer factorization can be done in polynomial time knowing how to do primality tests efficiently?

Is search a binary heap operation?

Why is NFA minimization a hard problem when DFA minimization is not?