ShreevatsaR
Reputation
28,050
290/100 score
 Aug 13 awarded Necromancer Jul 31 awarded Nice Answer Jul 27 awarded Yearling Jul 27 comment Recurrence relation with generating function problem I agree; that's part of why it's less simple in this case. Jul 22 comment Fast way to get a position of combination (without repetitions) @van E.g. on SO: stackoverflow.com/questions/3143142/… stackoverflow.com/questions/5307222/… (and many others). On this site: math.stackexchange.com/questions/349924/… (and many others). On Wikipedia: en.wikipedia.org/wiki/Combinatorial_number_system en.wikipedia.org/wiki/Factorial_number_system Terms to search for are "(ranking|indexing) combinations", also "combinadics", and names of those WP articles. Jul 22 comment Simple string permutations question The answer is correct, but if you're writing it up for homework / an exam etc., you should add that $\binom{5}{2}$ is the number of ways to allocate the positions of the vowels in the sequence. Jul 22 comment Playing roulette @nknj: Thanks, fixed. Jul 22 revised Playing roulette had switched signs Jul 21 comment Fast way to get a position of combination (without repetitions) This question has been asked before multiple times on both this website and StackOverflow; one of the existing answers may suit you. (That's assuming that your $\left(\!\!\binom{n}{k}\!\!\right)$ is just an odd way of writing $\binom{n}{k}$ because I don't know what else it could mean.) Jul 15 comment What is the most efficient numerical base system? @alex.jordan: Indeed, looks like I made exactly that mistake, thanks for pointing it out. Jun 28 comment search on a split data structure BTW, $b(n)$ is $n$ for the unsorted list as you always need to look at all elements before concluding it isn't there. Jun 28 comment Special representation of a number The remarkable resemblance of the two plots is interesting though, and I'm curious what the general shape (of the "upper" and "lower" curves) are. Jun 28 comment search on a split data structure It still wasn't clear so I've edited the question; take a look and see if that's what you intended. Jun 28 revised search on a split data structure quote Jun 28 comment search on a split data structure Can you edit the question to make it clearer in the formatting which parts are quotation from the test / homework / question, and which parts are your own thoughts / questions? Jun 26 comment How many algebras are there of finite-sized $\Omega$? I just got a notification because this answer was upvoted. Not only do I have no recollection of having posted this answer, I don't even understand it now. At all. Clearly the explanation could have been better! Jun 26 comment Expectation value of number of drawings of increasing sequences of labelled balls from an urn. @uomoinverde The bounty doesn't matter so much; what would be gratifying would be if you indicated that you understood the ideas better now. :-) Jun 26 comment Expectation value of number of drawings of increasing sequences of labelled balls from an urn. Note that the question asks for the probability that the number of drawings is greater than $k$, but you seem to be calculating $\Pr(X \ge k)$ instead of $\Pr(X > k)$ (which is what it asks for). Jun 26 answered Expectation value of number of drawings of increasing sequences of labelled balls from an urn. Jun 18 comment How to determine growth rate of coefficients of generating function @Michael Yes, their Chapter VIII on the saddle-point method covers such generating functions.