Tag: c++

Project Euler #308

You just gotta take a look at this one! It’s one of the absolutely coolest things I’ve seen recently πŸ™‚ A virtual machine with internal state consisting of just one integer number! And its instruction codes are… fractions! Whoa. It’s Turing-complete and unlike Brainfuck and some other quirky esoteric languages […]

File-based merge sort

Time for the file-based merge sort code promised long ago. BSD licensed. Yes, I know it’s way too verbose, quite inefficient and probably pretty ugly but hey it’s just a general idea for you to improve and adjust to your specific needs. It’s intentionally this clear πŸ˜‰ It can sort […]

I'm alive

I’m alive and well. In case you wondered what was stopping me from posting recently, the answer is PE #289, PE #294 and now the most recent PE #304. The last one was really easy (I had fallen asleep right before it was posted πŸ˜‰ and got to it the […]

Project Euler #303

For a positive integer n, define f(n) as the least positive multiple of n that, written in base 10, uses only digits <=2. Thus f(2)=2, f(3)=12, f(7)=21, f(42)=210, f(89)=1121222. Also sum_n=1^100 {f(n)/n} = 11363107 Find sum_n=1^10000 {f(n)/n}. Phew… this was an easy one πŸ˜‰ I made it to the top […]

Merge file sort and swap iterator

During my struggles with Project Euler Problem #302 I made an attempt to semi-brute force it. Unfortunately it required huge amounts of RAM (about 2e9 * 16 bytes) so I figured I could use some help from permanent storage. I implemented two helper classes, namely MergeSort and SwapIterator which look […]

Project Euler #300

In a very simplified form, we can consider proteins as strings consisting of hydrophobic (H) and polar (P) elements, e.g. HHPPHHHPHHPH. For this problem, the orientation of a protein is important; e.g. HPP is considered distinct from PPH. Thus, there are 2n distinct proteins consisting of n elements. When one […]

Paralell DP, BGL and other fun stuff ;)

I haven’t been posting for the past few days because I’ve been in WrocΕ‚aw (Breslau) for the weekend and then I was kinda busy playing with new coding quests, this time from topcoder.com, my second big love after Project Euler (jeez, why nobody told me about these two before? πŸ˜‰ […]

Open MPI convenience functions

I could start by lecturing you on the basics of usage and principles of operation of MPI and Open MPI in particular, but I think it might not be a good idea, because you (or even more probably me πŸ˜‰ ) could get bored really quickly. To cut long story […]

Project Euler #298 – Solution

Omg, I finally solved this problem and gained access to Project Euler’s thread dedicated to its solutions. Apparently everybody came up with basically the same idea. The number of game states can be reduced to 438 (439 including the empty state). This way all 50 rounds can be simulated using […]