MeowSolverStrategy · step 3 of 6
Confinement & locked sets
You do not need to know where a region’s cat goes to profit from knowing roughly where it must be.
The purple region lives entirely in row 2 — so row 2’s cat is purple, and the yellow and blue squares in that row are dead.
The purple region’s cat has to go somewhere in the purple squares — and every purple square sits in the same row. That row gets exactly one cat, and purple has now claimed it. Every non-purple square in the row is a cross, even though the cat’s exact position is still unknown.
The same logic runs in every direction: a region confined to one column claims that column; and mirrored, a row or column whose survivors are all one color claims that region — so the region’s squares outside the line all die.
Locked pairs and triples
The grown-up version: if two regions only have survivors in the same two rows, those two cats occupy both rows between them — every square of any other color in those rows is a cross. The same holds for three regions in three rows, and for columns. Meowdoku hard levels and late-game Queens boards lean on pairs constantly; triples and quadruples are rarer but MeowSolver checks for them too (they show up as “locked set” hints).
In double-cat play
At two cats per line the idea only gets stronger. A color confined to one row or column now claims both of that line’s cats — so every other square in the line still dies. And a new bonus appears when the color’s open squares are exactly four consecutive squares:
Purple’s open squares are four consecutive cells of one column. Its two cats claim the whole column — the squares above and below the run die — and wherever the pair lands, every square flanking the run is touched too.
Purple needs two cats among four squares in a line, and cats can’t touch — so the only legal pairs are top-and-third, the two ends, or second-and-bottom: every one of them leaves a cat within a step of all four rows. That means every square beside the run, in both neighboring lines, sits next to a cat no matter how the pair falls. Cross the whole flank, on top of the rest of the column. MeowSolver fires this as a Trapped colour hint — it outlines the trapped color’s squares and marks the line and flank crosses together.
How to spot it without exhaustive search
- Watch regions as they shrink. The moment a region’s survivors fit in one line, fire.
- Long skinny regions are born confined — check them before making any marks at all.
- Scan lines whose survivors look monochrome; that is the mirrored version staring at you.