Meowdoku 🐱

A "Queens"-style puzzle: on an n x n board, place one cat per row and per column, no two cats touching (including diagonally), and exactly one cat per color region.

Layout

• web/ — static HTML/CSS/JS. Just serve the folder, no build step.
• levels/<n>/level_<n>_<idx>.txt — level data, one text file per level.
• tools/ — Python level generator + solver, used offline (not shipped to the browser).

Play locally

cd web
python3 -m http.server 8000
# open http://localhost:8000

Level file format

8
AABBBCCD
AABBCCDD
AEBBCCDD
AEEBFCDD
AEEFFCGD
AEFFFGGD
HEFGGGGD
HHHHHGGD
# solution: 3 1 6 4 0 7 5 2

• Line 1: board size n.
• Next n lines: one letter per cell = color region id.
• Trailing # solution: ... comment: the intended solution's column for each row, 0-indexed. Ignored by the web client, useful for tools/ analysis scripts.

Generating levels

cd tools
python3 generate.py --sizes 8 9 10 11 12 --count 5 --seed 42
python3 build_index.py   # refresh web/levels_index.json

generate.py:

1. Picks a random cat placement (one per row/col, no two in adjacent columns on consecutive rows — the only way two cats could touch).
2. Grows one color region per cat via randomized flood fill.
3. Verifies the board has a unique solution with solver.py; if not, it locally re-recolors boundary cells to kill alternate solutions (a targeted repair, not a random restart) without ever disturbing the cats' own cells, then re-checks. Falls back to a fresh permutation if repair can't converge.

Notes:

• --count N numbers files 001..00N per size and overwrites existing files with those indices — it doesn't append. To add more levels without touching existing ones, generate into a scratch dir and copy over with indices past what's already there, or just bump --count and accept that low-numbered levels get regenerated (they're random anyway, so replacing them is harmless).
• Different --seed values (or omitting --seed) give different level sets. Same seed + same code = fully reproducible output.
• Runtime grows with n: n=8/9 take well under a second per level; n=11/12 can take several seconds to tens of seconds each, since a bigger board needs more targeted-repair iterations to reach a unique solution. Generating all of 8–12 at --count 5 takes a few minutes total — that's expected, not a hang.
• Always re-run build_index.py after generating, or the web client won't see the new level count.

solver.py also works as a standalone checker:

python3 solver.py ../levels/8/level_8_001.txt

Printing levels

Export boards to a print-ready A4 PDF — colour blocks only, white background, nothing else on the page:

# pack 6, levels 1-10 and 51-60, four boards per page -> meowdoku_6.pdf
python3 tools/gen-pdf.py --set 6 --level 1..10,51..60 --per-page 4

• --set — a pack: a board size (6..12) or hard / bad.
• --level — 1..10,51..60, 5-9, a single 7, or all.
• --per-page — 1, 2, 4 (2x2) or 6 (3x2). Default 4.
• --label — print each board's level number in its bottom-left corner.
• --out — output path. Defaults to meowdoku_<set>.pdf.

Needs no third-party packages; the PDF is written directly.