Find the Cat #172: 8x8 Grid Puzzle (Medium)

medium

Tap a square: ✕ (ruled out) → 🐱 (cat) → clear

0 / 8 cats · 0:00
Red (1)Orange (19)Yellow (8)Green (7)Teal (7)Blue (11)Purple (3)Pink (8)

A 8x8 logic grid, 8 colors, 8 cats. Work out where each cat sits using nothing but the rules -- there is only one correct layout and no guessing is needed.

  • One cat in every row and every column.
  • One cat in every color region.
  • Cats can’t touch — not even diagonally.

Step-by-step solution

Squares are written as R<row>C<column>, counting from the top-left. Cross out the squares listed, and place a cat wherever a step says so.

  1. The Red region has only one open square left: R1C3. Put a cat there.
  2. The Pink region has only one open square left: R2C5. Put a cat there.
  3. Wherever the cat in the Green region ends up, it rules out R8C7. Cross that square out.
  4. Wherever the cat in the Teal region ends up, it rules out R4C7. Cross that square out.
  5. Wherever the cat in the Purple region ends up, it rules out R7C1. Cross that square out.
  6. The Green and Purple regions can only use rows 7 and 8, so rows 7 and 8 are already spoken for. Cross out R7C4, R7C7, R7C8 and R8C8.
  7. Wherever the cat in the Yellow region ends up, it rules out R5C7. Cross that square out.
  8. Wherever the cat in the Blue region ends up, it rules out R4C4 and R6C6. Cross those squares out.
  9. Wherever the cat in the Yellow region ends up, it rules out R5C8. Cross that square out.
  10. The Green and Blue regions can only use columns 4 and 6, so columns 4 and 6 are already spoken for. Cross out R5C4 and R5C6.
  11. Wherever the cat in the Yellow region ends up, it rules out R6C1, R6C2 and R6C4. Cross those squares out.
  12. The Blue region has only one open square left: R4C6. Put a cat there.
  13. The Green region has only one open square left: R8C4. Put a cat there.
  14. The Teal region has only one open square left: R3C8. Put a cat there.
  15. The Yellow region has only one open square left: R6C7. Put a cat there.
  16. The Purple region has only one open square left: R7C2. Put a cat there.
  17. The Orange region has only one open square left: R5C1. Put a cat there.

About this puzzle

Where to start: the Red region is a single square, so its cat is already decided. Its 8 color regions range from 1 square (Red) to 19 squares. It can be solved in 17 deduction steps using grouped row/column/region deductions.

Start with the region that is a single square -- its cat has nowhere else to go. Cross out that cat's whole row, column and neighbors, then move on to the next-smallest regions: with only a couple of squares each, they leave very little room.

When you fill the last cat, press Check Answer -- the grid is verified against the stored solution and any broken rule is named so you know where to look.

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