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GP 2025 Sudoku 6 puzzle 12 Consecutive

published by DreamRose311 on Thu, 09/25/2025 - 05:12
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Player's feedback

I like to go back and do the puzzles I didn't solve during competition (presumably every one does? hehe).

I've stared at the puzzle a lot, and I can't even see where to get started. If anyone remembers how they solved it, can you give me a hint of your first move or two?

Submitted by Mike on Thu, 10/02/2025 - 03:39.

The key to this puzzle is parity.
Row 3 contains 4 consecutive pairs and R3C5. Because a consecutive pair consists of one odd number and one even number, and a set of 1-9 is 5 odd numbers and 4 even numbers, we can deduce that R3C5 must be odd.
Similarly, Row 1 and Row 2 contains 8 consecutive pairs, R1C5 and R2C5. These two rows contain two sets of 1-9, which is 10 odd numbers and 8 even numbers. Therefore R1C5 and R2C5 must also be odd.
With R4C5 and R6C5 also odd, now Column 5 already has 5 odd numbers, therefore the remaining four must all be even numbers. Since R5C5 cannot be consecutive with either 3 or 5, it can only contain the number 8. Similarly, R7C5 can only contain the number 6.

Submitted by DreamRose311 on Wed, 10/08/2025 - 07:23.

OMG I can't believe I forgot about parity *biggest face palm ever* As soon as I saw the title, I didn't even read the rest I just went to solving. What a fun puzzle that turned out to be. I usually love parity based stuff too, but done too many whisper lines lately . Thank you so so much for responding!!