Gram's blog has been pretty fun to follow. Like with Project Euler , I constantly want to implement each thing he talks about (e.g. Monadic Coconuts , Towers of Hanoi ). Here now is " The Wondering Ant ": open System.Drawing open System.Windows...

After reading the “coconut” problem over on my friend’s blog , I thought it would be fun to solve it with a silly brute force approach. First, go read his post and then come back here. let take n = let m = n - 1 // give one to...

A friend of mine is starting a pretty fun looking math blog . His first post is on Towers of Hanoi . I'm sure he'll tackle it with some slick mathematics, but my usual M.O. is to convert everything to code. I remember this "Hello Recursive World" from...

It’s fun dorking around with the HP 41CX emulator on the iPhone. It’s a near-perfect rendition. I forgot how much I loved RPN calculators. The 48GX looks even more interesting with Reverse Polish Lisp but I haven’t figured out how to use it yet. The 41CX...

";" galleryimg="no"> Babbage's Difference Engine is pretty fascinating. I had wanted to go see the one on display at the Computer History Museum in Mountain View, but now Nathan Myhrvold has the thing back in his living room! Maybe I’ll build...

Find the 10001st prime let naturals = Seq.unfold ( fun i -> Some(i, i + 1 )) let primes = naturals 2 |> Seq.filter ( fun n -> seq { 2.. int (sqrt (float n)) } |> Seq.forall ( fun x -> n % x <> 0 )) Seq.nth 10000 primes

Difference between sum of the squares and the square of the sum of 1 - 100 : ( fun ns -> let sqr x = x * x (sqr (List.sum ns)) - (List.map sqr ns |> List.sum) ) [1..100]

Smallest number divisible by each of 1 to 20 : First cut (takes almost an hour to execute!): let isFactor n d = n % d = 0 {1..Int32.MaxValue} |> Seq.find ( fun n -> [1..20] |> List.forall (isFactor n)) Second cut (takes a...

Largest palindrome from product of two 3-digit numbers : let isPalendrome n = let s = n.ToString() |> List.of_seq s = List.rev s seq { for a in 100..999 do for b in a..999 -> a * b } |> Seq.filter isPalendrome |> Seq.max

Largest prime factor of 600851475143 : let primeFactors n = let isFactor n d = n % d = 0L let nextFactor n d = seq {d..n} |> Seq.find (isFactor n) (n, 2L, []) |> Seq.unfold ( fun (n, d, a) -> if isFactor n d then Some(d, ((n...

Sum of even terms in Fibonacci sequence which are < four-million : (1, 1) |> Seq.unfold ( fun (a, b) -> Some(a, (b, a + b))) // fibs |> Seq.takeWhile ( fun x -> x <= 4000000) |> Seq.filter ( fun x -> x % 2 = 0) ...

Project Euler is pretty darn cool. It’s a bunch of mathematical problems that require programming to solve. I’m having fun doing them in F#. They start very simple but quickly become more difficult. Problem 1 is to find the sum of all the multiples...

I've been reading Seymour Papert 's Mindstorms book about Logo ; very interesting! I'm just dying to add Turtle Graphics to my little toy language from last post (BTW, a friend suggested I call it "Ape" and I think I will!). Logo with a twist What...

I read “ Thinking Fourth ” and also played with Joy and Cat some time ago, but honestly I had written them off as “toy” languages. Recently I’ve had renewed interest in concatenative languages after watching Slava Pestov’s...

A recent post to the Puzzles and Logic Problems alias at work: The problem below is an example of a cryptarithm – a basic math problem made more difficult by obscuring each digit with a letter or other symbol. B A R...

Mads Torgersen’s post the other day was very cool! The first time I really understood Lambda Calculus was from this little 8-page paper . Relating it to Scheme made it stick for me. After reading Dr. T’s post I was just now having some fun playing with...

Mr. GeekRaver and I were walking between buildings and, for some reason, talking about how silly it is that good ol’ Minesweeper was “glossed up” for Vista. He said he had written it for DOS in some tiny amount of C code ( http://www.bradygirl.com/Work...

These SICP lectures are great I tell ya! The two lectures on Streams (6a/6b) talk about implementing things with lazy lists. His examples are in Scheme but here’s my translation to C# using some of the new features in 3.0. For example, here is a lazy...

My current team is awesome! We’re a tight little team with an interesting history and have done some great work together. It’s a sad day though. Today was John’s last day. He’s going over to work on Seadragon -ish stuff – really, really cool project!...

Some years ago now, I had the pleasure of working with a great team building a very elegant publishing and rendering system for MSN. This was one the best times I’ve had at Microsoft. It was a revolutionary system for the time [1] based on transformation...

Back in late 2005 there was an internal contest sponsored by MED to get people using Compact Framework. I spent a long weekend building a little app to browse Microsoft building floor plans and find offices and conference rooms. I ended up winning some...

[I wrote this almost 14 years ago (20 FEB 1996. Today is 27 SEP 2009). Some of it is embarrassingly naïve, but I was just a (25 year old) punk kid back then. I was quite the anti-Microsoft/Intel, Java-head back then. It’s funny that despite...