On the latest project I am working, a mobile app, upon a certain action of the user on the server, I need to schedule a task to run exactly 24 hours later. Cron to the rescue! My first, naive idea, however, was to add a new cron job to the crontab whenever a user hit […]
My latest mobile project relies heavily on an API, so a lot of development time was spent defining, implementing and testing the API. During the process I used two tools mainly, and they were very helpful. Below you’ll find them in case you are in a similar position. 1. Apiary.io This neat little tool helps […]
The problem: Alex is attending a Halloween party with his girlfriend Silvia. At the party, Silvia spots a giant chocolate bar. If the chocolate can be served as only 1 x 1 sized pieces and Alex can cut the chocolate bar exactly K times, what is the maximum number of chocolate pieces Alex can cut […]
The problem: My Solution in Common Lisp (defun processString (line position) (if (< position (length line)) (progn (setf (nth (- (char-code (char line position)) 97) gemArray) (+ (nth (- (char-code (char line position)) 97) gemArray) 1)) (processString line (+ position 1)) ))) (defun outputResult (position n) (if (< position 26) (if (eql (nth position gemArray) […]
The problem: Calvin is driving his favorite vehicle on the 101 freeway. He notices that the check engine light of his vehicle is on, and he wants to service it immediately to avoid any risks. Luckily, a service lane runs parallel to the highway. The length of the highway and the service lane is N […]
The following problem comes from HackerRank: —– The Utopian tree goes through 2 cycles of growth every year. The first growth cycle of the tree occurs during the monsoon, when it doubles in height. The second growth cycle of the tree occurs during the summer, when its height increases by 1 meter. Now, a new […]
The problem: Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, … By considering the terms in the Fibonacci sequence whose values do not exceed four million, […]
The problem: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. The solution in Scheme: (define (remainder x y) (- x […]
First of you, if you are considering to learn functional programming, I highly recommend it. It’s one of the few programming paradigms that is really different from the usual imperative/procedural style. Depending on the language you choose it will definitely force you to think about programming in new ways. Lisp is a great choice for […]
I was curious to see how a program to solve the same problem would look like in C and in Lisp. I went ahead and solved the problem below in both languages, using a very similar approach. Take your own conclusions! ——— James got hold of a love letter that his friend Harry has written […]