I was recently asked to write a simple algorithm using recursion. I immediately baulked because the algorithm was so trivial and recursion was such a bad choice.
\nBut for novelty sake i wrote it up on the whiteboard. It was wrong, I didn’t put the termination condition in, but I don’t program whiteboards anyway and the fact that the problem was so stupid to solve as recursion had me befuddled.<\/p>\n
But it has made me think. Think about how bad the solution I wrote up was. I was asked to write a recursive solution, to a linear single loop problem, so I wrote it thinking like I was solving a problem which was best solved by recursion. Solution ran n^2, I knew it, was the biggest reason why I thought writing the algorithm with recursion was stupid.
\nLater I was thinking, it wouldn’t be that hard to make the recursion linear, its still a terrible way to solve the problem but at least its still linear.<\/p>\n
But it was only just now that the obvious truth hit me, you can turn any loop into a recursion trivially without changing the asymptotic performance (your performance will likely drop, and you’ll probably stack overflow, but the O notation won’t change). I had been so focused on the request for recursion that I didn’t do what I should have done, which is solve the problem the right way, and then make that fit the requirements. (Not that that is a good motto for general development…)<\/p>\n","protected":false},"excerpt":{"rendered":"
I was recently asked to write a simple algorithm using recursion. I immediately baulked because the algorithm was so trivial and recursion was such a bad choice. But for novelty sake i wrote it up on the whiteboard. It was wrong, I didn’t put the termination condition in, but I don’t program whiteboards anyway and … Continue reading Loops and recursion<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-74","post","type-post","status-publish","format-standard","hentry","category-random-musings"],"_links":{"self":[{"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=\/wp\/v2\/posts\/74","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=74"}],"version-history":[{"count":0,"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=\/wp\/v2\/posts\/74\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=74"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=74"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.themissingdocs.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=74"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}