# Tag Info

17

First, build a spreadsheet. This has links surrounding it so that I can see where things will be relative to each other. Then

17

A short formulation, in line with ​the accepted answer

13

Completed grid (tapa clues in red, pata clues in blue): Solution: The bottom right: Continuing in the middle: Coming around left: Let's look in the upper left: Hopefully finishing:

12

I thought I'd try my hand at writing a program for Mobius sudoku. I used the Z3 SMT solver (Python wrapper) for this. There isn't much of a "solution path" to describe: most of the constraints translate fairly directly, even the wrapping around of the columns. The main difficulty was The other constraint which required some care was: Here's the ...

10

I'm going to propose the answer as: First, take notice of: Secondly, take notice of: Additionally, it can be seen that: This leads me to believe that all of the aforementioned points would remain true in the blank square, and as such our only logical options are: Also, notice that: With this, we can conclude that: Note: I tried making sense with sides ...

8

Say I'm one of the residents of this island, and the Guru hasn't shown up yet. I'm a perfect logician, like all the rest of the residents... but I'm very forgetful. So, to help me remember things, I make little scale models of the island in my hut! Whenever I'm unsure of something, I make two models of the island, and then see how the other perfect ...

5

Your "parallel induction" is already happening in the generally accepted solution When the solution says "A considers that B considers that ...", B, C, and so on are all arbitrary people. So it does indeed extend to "A knows that everybody knows that...". However, you seem to be failing to take some uncertainty into account. What new ...

5

This puzzle is easier than it looks. First you have to realise that We then simply look at the row and column sums: Now that we know which cells have to change, it is simple matter to change them to make the sums equal to 246. These changes indeed happen to be a permutation of those six numbers.

5

For all of these questions, the real key is to look at the possible answers. Many times, the testers have one real solution in mind with 3 fake solutions that are adjacent by one thing to the real one. So, looking for majorities gives the following results: 3 times the right column is occupied, only 1 time the left => right column is correct 3 times the ...

4

Completion of proof: Observe that because of parity there actually have to be two bridging dominoes for every pair of adjacent rows/columns. Now count them: 5x2 horizontal + 5x2 vertical: That's more than we have at our disposal.

3

5 numbers are certainly enough to make it unsolvable. This is a simple example : You can never put one in the bottom left corner. Maybe someone has an optimization?

3

The answer would be Explanation: So with that information the answer is then

1

You are given four statements; let's rewrite them in more basic/formal notation. SUNNY implies WET. RAINCOAT implies SWEAT. RAINY implies (DRY and NOT SUNNY). (WINDY and NOT SUNNY) implies SWEAT EVAPORATES. In the given situation, it is RAINY and WINDY and you wear a RAINCOAT. By 2, you SWEAT. By 3, you are DRY and it is NOT SUNNY. By 4, your SWEAT ...

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