While I’ve been getting a fair few programming exercises from Reddit’s /r/dailyprogrammer, more recently I’ve started following a few other sub-Reddits, such as /r/programming and /r/netsec. While browsing the former, I came across this intriguing gem of a problem: HashChallenge: can you find the lowest value SHA-512 hash?
There was a new post on Programming Praxis a few days ago that seemed pretty neat:
Given a positive integer n, compute the prime factorization, including multiplicities, of n! = 1 · 2 · … · n. You should be able to handle very large n, which means that you should not compute the factorial before computing the factors, as the intermediate result will be extremely large.
Here’s another one from /r/dailyprogrammer:
… Your goal is to color a map of these regions with two requirements: 1) make sure that each adjacent department do not share a color, so you can clearly distinguish each department, and 2) minimize these numbers of colors.
Essentially, graph coloring.
Here’s a quick problem from the DailyProgrammer subreddit. Basically, we want to calculate the radius of a graph:
radius(g) = \min\limits_{n_0 \in g} \max\limits_{n_1 \in g} d_g(n_0, n_1)
Here’s a quick little programming task that I came to via a post on L2Program (who in turn seems to have found it on Reddit). The basic idea is to take a given list of circles and to determine the area enclosed (while correctly accounting for overlap).
Another quick one, this time from /r/dailyprogrammer:
Your goal is to write a program that takes in a list of edge-node relationships, and print a directed adjacency matrix for it. Our convention will follow that rows point to columns. Follow the examples for clarification of this convention.
This one has been sitting in my backlog for a while and its been a while since I’ve gotten to write a programming post1, but now seems as good time as ever: Twitter puzzle
Last week we parsed some music. That post was in a bit of a hurry, so we had to leave off a fair few important pieces (like ties and slurs for one; chords for a rather bigger one). We’ll get to them soon, but for now we want to actually get something playing back.
It’s been a bit, but as you may have noticed life is a bit mad at the moment. But I’ve still made some progress.
When we left off last time, we’d finished the first step towards making some lovely music with Racket: tokenization. Now we want to take those songs and form them into something actually approaching music.