How did I hacked Linaro Connect BKK19 puzzle

One of Linaro Connect traditions is a puzzle to solve. Created by Dave Pigott. And recent BKK19 event was not any different. There was puzzle announcement on the first day — right before first keynote. But no one could be first to answer at that time…

Tuesday

As usual before Connect I looked at a map and marked several locations in Bangkok as places to visit. Then took a look at the official BKK19 application. Installed it on my phone and started.

First screen had few paragraphs of text. Some information about the event and schedule. But there was also paragraph with information about the puzzle. WITH the link to it!

I clicked to get some redirection to Google Forms website. With information that this form is not available for users outside of organization. As I do not have work accounts on my phone I checked for redirection link and loaded it on my desktop. And landed into the puzzle.

Puzzle form

It was a bit different than version provided during Linaro Connect. There was a graphics with seven (official one had eight ones) columns of text. Under it was graphics with chess figures:

H1 G3 F1 H2 G4 E3 D1
A4 C3 B1 A3 C4 B6 A8
B5 A7 C8 D6 E8 F6 D5
G8 H6 F5 G7 H5 F4 E2
C6 A5 B7 C5 A6 B8 D7
F3 G1 H3 G5 H7 F8 E6
F7 H8 G6 H4 G2 E1 D3
A2 B4 C2 A1 B3 D2 E4

Graphical hint

Dave later said that knight was not present in it but I did not noticed that. There was a plan to add that graphics into official puzzle if no one provides proper answer until Wednesday.

From text I noticed that it is chess related. Took a sheet of paper, draw 8x8 grid on it and started following each row on it with different markings each time. Hm… nothing came to my mind. Noted missing entries.

Help me Google, you are my only hope

Then started googling “knight chess puzzle” and got “knight’s tour” links on first page. Started reading what it is about. Then restarted tracking knight’s moves from the puzzle with adding missing ones. Turned out that this was it.

Let me mail Dave

I submitted “knight’s tour problem” as the answer and wrote to Dave:

I see that they are online already.

Are the ones there official ones or testing one?

Turned out that I found testing version. Which did not even collected emails when someone provided an answer. But there was one such sent so Dave marked it as my submission. And the link got removed from BKK19 application.

At pool bar

I arrived in Bangkok on Saturday. Met Dave at pool bar and we had a chat about the puzzle. Was fun to see how surprised people around were that first answer was already provided. I asked Dave to not give me the proper answer nor info was my answer good so I would not spoil other people.

During Connect few attendees asked me about the puzzle, how it went. Kept away from spoiling them.

And the winner is…

Then Friday happened with closing remarks session. Only a few people provided two words answer (“knight’s tour”) and few three word one (“closed knight’s tour”). My name was in “special mention” section.

Puzzle winners slide

Turned out that there is separate award for hacking a puzzle. It was 3rd time when it happened. I got a waterproof action camera (EZVIV S1C model) — will find some use for it sooner or later ;D

Whole puzzle was fun. Thanks go to Dave for creating it and providing me with a copy of both results slide and graphical hint so I could use it in blog post.

linaro linaroconnect