2023 Puzzle Grand Prix

[pinkagape]

For Round 3, has anyone got any hints for the Criss Cross Loops? I can't work out how to start it, short of putting in a word and seeing what happens.

[sstackho]

I also didn't see a logical way to break into this puzzle. I rarely skip a Grand Prix puzzle (other than those damn Letter Weights ones), but this one didn't feel worth my time.

[david mcneill]

Nothing easy about the example puzzle. I identified 16 possibilities for the central line of 3 cells where the CIR ends up but I had to go through these by a process of elimination.

[pinkagape]

In Round 6, the last Snake Pit got me in such a tangle. Can anyone help me with the snake that goes through R3C3? That ate so much of my time and everything I tried seemed impossible.

[detuned]

That one resolves itself reasonably quickly:

R1C1 is a 2-snake going right or down.

If down then things break quickly:
- R3C1 must go right (if down it’d be a 2-snake adjacent to another 2-snake, which is forbidden). Let’s call this A.
- similarly R1C2 goes down. Let’s call this B.
- A and B don’t join, otherwise they’d be a 4-snake adjacent to another 4-snake in R3C3. So B goes right, A goes down.
- now R3C3 must go up to join with B
- A must now escape further as it can’t join the clues in column 3, coming down at least as far as R6C2.
- This forces a 2-snake in R4-5 C1
- R6C1 must now come right to avoid being a 2-snake, thereby joining A to form a 6-snake
- this breaks R6C3.

So R1C1 goes right, the ensuing logic is similar, but you can avoid the equivalent contradiction given the different valued clues in row 3.

In general the structure of the puzzle alternates lots of 2-snakes on the border with longer snakes poking into the middle.