Today’s five minute post brought to you via Programming Praxis / Career Cup:
Given a positive integer, return all the ways that the integer can be represented by letters using the mapping 1 -> A, 2 -> B, …, 26 -> Z. For instance, the number 1234 can be represented by the words ABCD, AWD and LCD.
Here’s another post from /r/DailyProgrammer: Advanced Langton’s Ant. I’m a bit behind the times (see tomorrow’s post), but it’s still an interesting enough exercise, so let’s go for it!
If you were paying attention when I posted part 2 to GitHub (pegs.rkt), you might have noticed a function I hadn’t talked about: play
Hey, remember that post a few days ago about the Cracker Barrel peg game? Right at the end, I mentioned that there would be a part two, all about how to bend the puzzle at least a bit to your advantage. Basically, rather than finding the first solution to the peg game, we’re going to find all of them. From there, we can determine which moves are easier to win from, which are harder, and which are downright impossible. Let’s do it!
Ever been to Cracker Barrel? Remember that peg game? It seems that rather a few people are interested in how to solve it: Google. Let’s do that.
Another five minute challenge1, this time from /r/dailyprogrammer: given any positive integer, create and render a factor tree.
Five minute post from Programming Praxis:
Write a function to return true/false after looking at a string. Examples of strings that pass:
{}, [], (), a(b)c, abc[d], a(b)c{d[e]}
Examples of strings that don’t pass:
{], (], a(b]c, abc[d}, a(b)c{d[e}]
Here’s a fun little bit of code for you:
55*4*v _ v
v <>:1-:^
|:<$ < ,*48 <
@>0"zzif">:#,_$ v
>:3%!| >0"zzub">:#,_$^
>:5%!|
v "buzz"0<>:. ^
|!%5: <
>:#,_ $> ^
Gibberish you say? No! Befuge!
What would you do if you were on a machine that had no higher level graphics, but you still wanted to display images?
About two weeks ago, I came across a post via /r/programming: Quadtree Art(src). In a sentence, the goal is to recursively divide an image into a quadtree, at each step expanding the current node with the largest internal variance.