Triangle Trilemma

2013-01-20

Four points, a square?) and comes originally from a Google Code Jam problem. The problem is stated simply enough

Accept three points as input, determine if they form a triangle, and, if they do, classify it at equilateral (all three sides the same), isoceles (two sides the same, the other different), or scalene (all three sides different), and also classify it as acute (all three angles less than 90 degrees), obtuse (one angle greater than 90 degrees) or right (one angle equal 90 degrees).

But once you start implementing it, that’s when things get more interesting. 😄

Translate CSV to HTML

2013-01-16

Yesterday’s post from Programming Praxis asks us to write a function that will read content formatted as comma-separated values and output the result as an HTML table. Their solution uses the text file database library that they posted about (which is a neat concept, you should check it out), but I think I’m going to work out the solution more directly.

Wombat IDE - It's Alive! (bug fixes)

2013-01-06

It’s alive!

I haven’t worked on Wombat in a while, but with the new semester quickly approaching, I figured that it would be a good time to take out a few of the outstanding bugs on the issue tracker. Granted, there’s still a fair few, but it’s a start.

Four points, a square?

2013-01-03

Another post from Programming Praxis. This one was originally intended for Friday but they posted it early, so I figured I would go ahead and do the same. The problem is actually deceptively straight forward:

Given four points, do they form a square?

Happy New Year

2013-01-02

Yesterday’s post from Programming Praxis asks us to build a very special sort of expression. Using the numbers 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 in that order along with the operators of multiplication, division, addition, subtraction, and concatenation, find all of the ways that we can write an expression totaling 2013. Here’s one valid solution:

109 - 8 * 7 + 654 * 3 - 2 / 1 = 2013

Parallel BF

2012-12-31

Getting a bit close to the deadline, but I think I have something that’s pretty interesting. Basically, it’s the same BF interpreter that I wrote about yesterday with four additional commands:

&	Spawn a new thread; set the current cell to 0 in the parent and 1 in the child
~	Kill the current thread
!	Send a ping on the channel specified by the current cell
?	Wait for a ping on the channel specified by the current cell

Nested Primes

2012-12-22

Yesterday’s post from Programming Praxis poses an interesting problem: find the largest prime n such that the result of repeatedly removing each digit of n from left to right is also always prime.

For example, 6317 would be such a number, as not only is it prime, but so are 317, 17, and 7.

Narcissistic Numbers

2012-12-14

Today’s post from Programming Praxis posits an interesting problem: how can we (efficiently) find all of the narcissistic numbers (in base 10)?

Generating non-repeating strings

2012-12-12

Based on this post from Programming Praxis, today’s goal is to write an algorithm that, given a number N and an alphabet A, will generate all strings of length N made of letters from A with no adjacent substrings that repeat.

So for example, given N = 5 and A = {a, b, c} the string abcba will be allowed, but none of abcbc, ababc, nor even aabcb will be allowed (the bc, ab, and a repeat).

It’s a little more general even than the version Programming Praxis specifies (they limit the alphabet to exactly *A = {1, 2, 3} *and more more general still than their original source which requires only one possible string, but I think it’s worth the extra complications.

Numbers of Wirth

2012-12-10

Niklaus Wirth gave the following problem back in 1973:

Develop a program that generates in ascending order the least 100 numbers of the set M, where M is defined as follows:

a) The number 1 is in M.

b) If x is in M, then y = 2 * x + 1 and z = 3 * x + 1 are also in M.

c) No other numbers are in M.

(via Programming Praxis)

It’s an interesting enough problem, so let’s work out a few different ways of doing it.