Drainers and Sires
(Published on 23. June 2025, 15:52 by mathpesto)
Rules:
Normal sudoku rules apply.
Killer: Digits cannot repeat in a cell and the values sum to the given clue.
There are two types of vampire cells: drainers and sires. Each type appears exactly once in every row, column, and box. The digits 1–9 appear once each among drainers, and once each among sires. Vampire cells cannot touch, not even diagonally, and they cannot consume the same prey.
Drainer: A drainer cell bites a neighboring cell (orthogonally or diagonally adjacent). The drainer's value equals the sum of its digit plus the digit in the prey cell. The prey's value is 0 (e.g. a 7 bites a 4; the drainer value is 11 and the prey value is 0).
Sire: A sire cell bites a neighboring cell. The sire's value and the prey's value are both equal to half the sum of their digits (e.g. a 7 attacks a 4; the sire value is 5.5 and the prey value is also 5.5).
Solve online:
Solution code: Digits in Column 8 (top to bottom)
Comments
on 5. July 2025, 07:24 by ddx02
Wonderful puzzle!
on 25. June 2025, 16:01 by GoodMorningCallum
I thoroughly enjoyed this. What an awesome puzzle, with some fascinating logic, especially the way the vampires interact with each other! It was challenging, but had a really smooth solve path. Thank you very much.
on 25. June 2025, 03:14 by skuntsel
Amazing puzzle with quite interesting logics, solving very smoothly. Extremely clever use of disjoint set, liked that a lot. Thanks, Math Pesto!
on 24. June 2025, 15:08 by Snookerfan
Gorgeous puzzle! Very well set to get the most unexpected interactions. Thank you
on 23. June 2025, 17:33 by Piff
Very nice, enjoyed it a lot
on 23. June 2025, 17:23 by Fool on Hill
Enjoyed this a lot - tricky, though: some cool things hidden in there. The rule allowing diagonal interactions was used well, but required care to take into account every possibility. Thanks for setting
on 23. June 2025, 15:57 by sanabas
Enjoyed this one a lot. Very interesting interactions between the two vampire types.
