[BUG] Indiana 2 (but influences all versions)

Hello everybody, this is my first post here. Unfortunately I can not upload photos due to restriction for new users so let me explain using just “text”:

I think there is misleading description related to the green and red arrows. And it actually causes a bug in Indiana 2 Test case “02 Broken Sewer”.

Cell 6x1 is type 12 (top right “curve”). But Type 12 has arrow only in one direction and even after rotating it, it will never allow Indi to go through.

After I assumed that movement in both directions is possible, then test passes.

I read some comments related to cell types and other users also are confused because of green/red arrows.


Type 12 has a green arrow from the right, meaning that you can enter it from the right. Indy enters from the left, so no, he will never be able to enter this 12 room. You have to rotate this room to obtain one which will have a green arrow, entering from the left. Here, type 13 works: https://www.codingame.com/replay/solo/53275901

For rooms with a red arrow, movement in that direction is not possible. If your program works better by assuming otherwise, it is probably a bug in your program. And if your solution requires that behavior and does pass the test (for example if during the replay indy does enter a type 11 from the left and survives), then it is a bug in the validation script. But I doubt it. :wink:

Hmm, I don’y think it is possible to change the cell type. Only rotation is possible of course. But take closer look on cell type 12 and arrows. Originally, cell is placed so the arrow is from RIGHT to BOTTOM. We have to rotate it clock wise once. Now, the arrow is from BOTTOM to LEFT. Indi is comming from LEFT and - according to cell type 12 rotated once clockwise - He is not able to move through.

I assumed in my code, that cells 12 and 13 has arrows in both directions - then everything works just fine.

What I wan to say is that cells description is misleading. Users do not know if green arrows mean the ONLY available moving direction or it is just a hint about movement.

The arrows are indicating how you can enter the room, they are not part of the room itself. They don’t rotate with the room! :wink:

And for this reason, it is possible to change the cell type, precisely by rotating : when you rotate a type 12 “right”, what you obtain is a type 13 room.

There is no need for clarification on the arrows in my opinion: you correctly understood that the green arrows do mean the only possible directions, for that room. Maybe the fact that rotating the room effectively changes one into another could be made more explicit, though.

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I am still not convinced and I think green arrows ARE important and part of the constraints.

Prove ;):
Check the cell types: 1, 7, 8 and 9.
Without green arrows we can not assume the possible INs and OUTs because it should be only 1 OUT for 1 IN. Otherwise it will not be deterministic. It means - green arrows ARE important. Why they are crucial for 1,7,8,9 cells but they are not for 12 and 13? This is not consistent - and this is what I wanted to point out.

Of course rotating 12 turrns into 13. BUT if this is so obviouse (rotating is part of the task), then why these 2 types are shown - as they are “equal” if we take into account rotation, but e.g. path from TOP to RIGHT (rotated version of cells 12 and/or 13) is not on the list? Still - this is inconsistent.

Those would be rooms 10 and 11. :wink:

There is only 1 OUT, so in particular only 1 OUT for each IN.

Green arrows are crucial for all rooms, this is true! But my point is just that they don’t rotate with the room. When you rotate a room, you have to see what room you get, and then go check what possible IN and OUT this room has.

Think of it in terms of game logic if it helps: Indy cannot go up, and cannot run into a wall with no obvious direction. That’s the physics, if you want. All rooms and arrows are given to make it clearer what these rules imply. Now, when you rotate a room, you don’t rotate the rules of physics with it!

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Exactly!! And here red arrows appear and I don’t understand “why” (read further).

[quote=“Skywalker_, post:6, topic:903”]
[…] they don’t rotate with the room. When you rotate a room, you have to see what room you get, and then go check what possible IN and OUT this room has.[/quote]

This explains a lot! But (what I still want to point out) this is NOT mentioned in description. Why not to make description cleaner instead of creating different cell types with arrows?

[quote=“Skywalker_, post:6, topic:903”]
Think of it in terms of game logic if it helps: Indy cannot go up,[/quote]

That’s the point!!! This rule is NOWHERE written in description!!! This rule would be (almost) enough to get rid of most of the cell types and misleading explanations.


Once again me. NOW I GOT THE IDEA. Thank You Skywalker_ for guiding me.

The information is written in Indiana 1 description and lack in Indiana 2 and 3.
As it was initially part of a challenge, one solving Indiana 1 was sent to Indiana 2 and knew all that.

We will soon revise this puzzle.