Find the Cat #237: 10x10 Grid Puzzle (Hard)

hard

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

0 / 10 cats · 0:00
Red (15)Orange (7)Yellow (7)Green (5)Teal (4)Blue (1)Purple (11)Pink (15)Brown (11)Grey (24)

A 10x10 logic grid, 10 colors, 10 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 Blue region has only one open square left: R7C8. Put a cat there.
  2. Wherever the cat in the Orange region ends up, it rules out R9C10. Cross that square out.
  3. Wherever the cat in the Yellow region ends up, it rules out R1C10, R2C10, R3C10, R4C10, R5C10, R6C10 and 1 more. Cross those squares out.
  4. Wherever the cat in the Orange region ends up, it rules out R10C6 and R10C7. Cross those squares out.
  5. Wherever the cat in the Green region ends up, it rules out R3C4. Cross that square out.
  6. The Teal and Purple regions can only use rows 1 and 2, so rows 1 and 2 are already spoken for. Cross out R2C1, R2C3, R2C4, R2C6, R2C7 and R2C9.
  7. Wherever the cat in the Green region ends up, it rules out R4C2. Cross that square out.
  8. The Orange, Yellow and Brown regions can only use rows 8, 9 and 10, so rows 8, 9 and 10 are already spoken for. Cross out R8C1, R8C2, R8C3, R8C4, R8C5, R9C1 and 3 more.
  9. The Red region has only one open square left: R6C2. Put a cat there.
  10. Row 2 has only one open square left: R2C5. Put a cat there.
  11. Wherever the cat in the Green region ends up, it rules out R1C3, R4C4 and R10C3. Cross those squares out.
  12. The Teal region has only one open square left: R1C1. Put a cat there.
  13. The Pink region has only one open square left: R5C4. Put a cat there.
  14. The Green region has only one open square left: R3C3. Put a cat there.
  15. Wherever the cat in the Brown region ends up, it rules out R4C6 and R9C7. Cross those squares out.
  16. The Orange region has only one open square left: R10C9. Put a cat there.
  17. The Yellow region has only one open square left: R8C10. Put a cat there.
  18. The Brown region has only one open square left: R9C6. Put a cat there.
  19. The Grey region has only one open square left: R4C7. Put a cat there.

About this puzzle

Where to start: the Blue region is a single square, so its cat is already decided. Its 10 color regions range from 1 square (Blue) to 24 squares. It can be solved in 19 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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