Your career as a hacker brings you more and more unreasonable tasks. Today you arrive at the ferry station, head to your next gate (no one mentioned if you even got an ice cream), and figure out where to seat. Even though you are the first person in the waiting area that does not stop you from knowing the seating habits for all other passengers, and calculate their seating patterns.
After you finished hacking the plane, your laptop dies: you forgot to charge it! Rookie mistake, or the calculations do consume a lot of power. The plane has a power outlet, but somehow it’s a non-standard one, you need an adapter. But first a cocktail! Then you empty your backback on the seat next to you and find out that you have dozens of different adapters, which you can stack together. None of them really work, and hopefully you don’t blow another fuse, or set the plane on fire!
Uh oh, either the ice cream at the airport was bad, or the cocktails are not good for you! How else can you explain that you hack the airplane systems with some paperclips and break the XMAS encryption, while the plane is airborne? The plane’s on-board systems emits some cryptic numbers and your task is it to decrypt this. Wait, did I say task? Who gave this task to you? Oh well, please be careful, if you shorten a circuit you might as well crash your own plane.
You fixed the colours of the bags yesterday) and security allowed you to leave the baggage section and go get your ice cream before you board your next flight. On the flight the kid next to you recognizes you as the great hacker you are, and asks you to fix a problem with the handheld game console. Go and hack the bootloader while no documentation is available because the mobile internet is off. Turns out someone coded an infinite loop into the bootloader, and missed that fact during testing. What testing, do you ask? Well, let’s not jump too deep into details, you have to hack a bootloader and make a kid happy. It’s Christmas soon, after all! And your cocktail is waiting!
They really trust you a lot … Now all flights are delayed, that’s quite usual in advent times. Except it’s
2020 and no one is traveling anyway. But they also impose more regulations, and now bags need to have colours, and bags need to go into other bags. And someone has to figure it out. That’s right, it’s you! I hope the stopover is long enough to at least grab some ice cream!
The flight is approaching a regional airport, but you still have to fill out a customs form. Since you are good with hacking things together, you walk around the plane and gather all the answers from all groups on the plane. There are
26 yes-or-no questions, marked from
Pretty amazing the tasks they ask you to do “on the fly”: Yesterday we fixed the passport scanner, today you have to write a piece of code which scans all the boarding passes in your environment (no one said they all carry them in the hand, and show it to you), and while waiting in the gangway you also have to identify your designated seat. Because, you know, you are such a good hacker you lost your boarding pass on the way from the gate to the plane ;-)
The challenge for day 4 is more suited for databases. The input is fuzzy, but with a CTE or two I should be able to clean it up. Solved the first part already with the kid earlier, but we decided to skip part two: mainly because it involved more complex string operations (best suited for regex operations), which is something the kid hasn’t learned yet.
Have to admit, on first glance this challenge looks a bit complicated. It’s well suited for languages which can do string manipulations, but it’s not well suited for PostgreSQL. Earlier today I already looked at this problem together with the kid, in Python. Therefore I already knew that I have to jump multiple rows as well. To sum it up: adjust x, including overruns, jump multiple rows in y direction, count trees along the way. All in a single SQL query.
Decided to do the map search in a pl/pgSQL instead, and write a function for it.