programming challenge – maxpagani.org

Elf and Guards – Days 5 and 6

Posted on 2024-12-062024-12-07 by max Leave a Comment

It couldn’t last forever—spending consecutive days writing about my progress in the Advent of Code took too much time and the rest of my life knocked on the door. In this post, I will try to update you quickly on days five and six.

On day 5 we had to assist an unfortunate handbook printer to get the updated pages in the correct order. Being magic-elven stuff, the proper order is not the natural increasing order of integers, but a custom order defined by number pairs – e.g. 43|12 means that page 43 has to be followed immediately by page 12. But stuff is not that simple, the order relationship is not linear like a–b–c, but may branch, so to give you an idea, after a may come either b or d and then are both followed by c.

Finding XMAS – Day 4

Posted on 2024-12-042024-12-04 by max Leave a Comment

Day 4 of the Advent of Code presents you with two new puzzles based on the word search puzzle idea. For some reason, you are teleported to the Ceres Elven Station (that made an appearance in AoC 2019), but there’s nothing for you to see here (yet) – not even the chief historian we looking for. So a small elf asks for your help to solve her word search.

Being Xmas elves the word you have to look for is “XMAS”, it can be written straight or reverse and can be written in any direction left, up left, up, up right, right down right, down and down left.

Elves’ Programming Language – Day 3

Posted on 2024-12-032024-12-03 by max Leave a Comment

There are plenty of programming languages and, of course, Xmas elves have their own. Although your main goal is still to find the Chief Historian, we are now in a warehouse, historian minions are wandering around looking for their boss and we are tasked to fix the computer¹.

This puzzle seemed a bit easier than the first two days, but I found it somewhat underspecified. You have to scan a text for patterns like “mul(n,m)” with n and m integers. For each pattern multiply n by m and sum all the products together.

Elves’ Advent Quest – Day 2

Posted on 2024-12-022024-12-02 by max Leave a Comment

After warming up with the first day’s puzzle, here we are with the second day. The bar is still low, but not as low as yesterday. With the coordinates decoded in the last puzzle, everyone runs to the nearest location which happens to be a nuclear plant (for reindeer needs). While we are here the elves running the plant ask for your help to analyze some data looking for anomalies.

Yes, we are in a hurry to look for the chief historian elf, but we also have 25 days to fill with puzzles. So here we go.

Fun with Functors in C

Posted on 2024-07-272024-07-27 by max Leave a Comment

C language is old, actually, a very old language that resisted all the innovations that impacted the software development industries. Even ISO standard Cobol integrated object-oriented capabilities in 2002!

This didn’t prevent programmers from applying object-oriented programming to C. With some macro juggling and a lot of self-control not to break framework rules, you can have inheritance and dynamic dispatching.

Generic programming is, in the same way, foreign to C language¹. You can use preprocessor macros to implement generic containers or functions that can be instantiated on the type you need, but it is a painful endeavor.

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The Advent of Scala Code – What I Learned

Posted on 2024-01-192024-01-19 by max Leave a Comment

It all started with an innocent-looking question, from a colleague – “This year I’d like to propose an office leaderboard for the Advent of Code, what do you think?”. Well, why not? I made a lame attempt at AoC some years ago and possibly gave up on the first day for lack of time (and commitment).

But this looked like an interesting challenge and I agreed and promoted the idea. Since I miss working in Scala, I wrote AoC solutions in Scala 3 to dust off some rust (ops) and learn the new syntax. Solving a (double) puzzle a day for 25 days (Xmas day included), is not a light endeavor. It requires at least from 1 to 2 hours and is increasingly difficult to squeeze into a normal working day especially if you have a life.

Speak Slowly, no Vowels, pls – Solutions

Posted on 2023-03-192023-03-19 by max Leave a Comment

In my previous post, I described how I devised a programming problem for an internal company contest with the help of the ubiquitous ChatGPT. Also, ChatGPT provided a solution for the problem as part of the development process. Even more interestingly the language model provided a fictional context for justifying the problem.

The task was to write a function removeVowels( string text ) which takes an arbitrary text (arbitrary as long as it contains no uppercase letters) and returns the same string where vowels have been removed. Given the string “hello world”, the result should be “hll wrld”.

The implementation must not have:

loops
if statement
list comprehension

If you want to give it a try before reading the solution, stop here. Otherwise, follow me.

Speak Slowly, no Vowels, pls – The Problem

Posted on 2023-03-132023-03-13 by max Leave a Comment

As a winner of the last programmer contest at Schindler MIL, I had to devise a new compelling and intriguing puzzle to propose to my colleagues. The first two puzzles were in the form “Implement X without using Y“, an interesting pattern that allowed for multiple solutions.

But I ran short of (X,Y) pairs, and staring at my blank page I decided to resort to … ChatGPT. Yes, nowadays it is like the uber-solution to everything. Don’t you know how to partially specialize your templates? Ask ChatGPT; don’t you know how to present a topic? Ask ChatGPT; don’t you know how much a brick weighs? Ask ChatGPT; don’t you know how to devise a programming puzzle? Ask ChatGPT.

So I went on and asked this modern oracle –

Lambda Headache for Mere Mortals

Posted on 2022-09-292022-09-29 by max Leave a Comment

A few years ago I attended a talk at a Lambda World Conference about Lambda Calculus. Although not an eye-opener (in fact that level of abstraction is rarely needed, nor advisable, in everyday programming), it was thought-provoking. By wisely crafting mathematical functions you could describe algorithms, fully equivalent to the good old recipe-like imperative programming code.

The point is that those lambda functions are really twisted.

Reading some anecdotes about Alonzo Church it is immediately clear he was quite a guy. And devising lambda calculus required quite a mind.

Since lambda calculus is just functions, no statement, it came to my mind I could use it to devise a solution to my “if-less” programming quiz.

The solution I prepared was too complex to be explained in my previous post, so I decided to write this post.

What if “if” would go missing?

Posted on 2022-08-122022-09-21 by max 2 Comments

In my last post, I described the first Schindler Milan office weekly riddle. It has been a big success, and it had a brilliant winning solution (one of mine 🙂 ). A simple problem, implementing increment by one without using addition, yet open enough to trigger a good number of solutions.

As the winner, it was my duty to invent the next riddle. A really daunting task if I wanted to live up to the expectations. Honestly, I didn’t invent anything, I just squeeze the web looking for a good programming riddle in the drops.

Eventually, I decided to go for determining the lowest of two numbers… using if-less programming. After all, if statement can be tricky and someone already pointed out that if statement should be considered harmful in the same way the infamous goto is.

Tag: programming challenge