After PhillyETE, I wanted to try out some Clojure, so I decided to solve the first problem of Project Euler. I coded up my own solution using some of the references on the Clojure site.

### Project Euler Problem Description, from Project Euler

Find the sum of all the multiples of 3 or 5 below N. (N is 1000 is this Project Euler problem.)

### Solutions

#### My first attempt

(def nmbrs (range 0 1000)) (def multiples (filter #(and (not= % 0) (or (= (rem % 3) 0 ) (= (rem % 5) 0 ) ) ) nmbrs ) ) (reduce + multiples)

#### Another attempt by a different author

Afterwards, I came across a terser, more elegant solution on a site that seems to have had the same idea as I did, Learning Clojure with Project Euler. The site had a really elegant looking solution:

; //grok-code.com/367/learning-clojure-with-project-euler/ (defn problem01 [limit] (reduce + (filter #(or (zero? (mod % 3)) (zero? (mod % 5))) (take (- limit 1) (iterate inc 1))))) (problem 1000)

#### My revised attempt

The use of take and iterate are really interesting. I haven’t encountered these “lazy” functions, and was surprised when I tried to run (iterate inc 1) in the REPL. I decided to modify my version with some of the things I learned from the version above, and make it more terse.

(defn problem01 [upper] (reduce + (filter #(or (zero?(rem % 3)) (zero?(rem % 5)) ) (range 1 upper) )) )

I’ll be working on some more of the problems in the coming days.

(PS. If you are wondering why I use *rem* instead of *mod*, it’s because I am using an older version of clojure with TextMate–I’ve yet to upgrade)

New blog post: Project Euler Problem 1 Solutio… /programming/project-euler-problem-1-solution-clojure/

This comment was originally posted on TwitterIf you install Homebrew (//mxcl.github.com/homebrew/), installing Clojure is as easy as:

brew install clojure

Cool, I will keep that in mind. I am currently using a clojure version that came with a TextMate bundle. Unfortunately, there are no instructions to upgrade. I’m going to keep trying though.