Find the Cat #236: 10x10 Grid Puzzle (Hard)

hard

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

0 / 10 cats · 0:00
Red (9)Orange (15)Yellow (9)Green (15)Teal (8)Blue (13)Purple (17)Pink (6)Brown (1)Grey (7)

Find the 10 hidden cats. Each row, each column and each colored region holds exactly one, and cats never sit on neighboring squares, diagonals included.

  • 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 Brown region has only one open square left: R6C4. Put a cat there.
  2. Wherever the cat in the Red region ends up, it rules out R9C2. Cross that square out.
  3. Wherever the cat in the Teal region ends up, it rules out R4C5, R7C6, R8C6 and R9C6. Cross those squares out.
  4. Wherever the cat in the Grey region ends up, it rules out R4C1. Cross that square out.
  5. Wherever the cat in row 1 ends up, it rules out R2C9. Cross that square out.
  6. The Red, Pink and Grey regions can only use columns 1, 2 and 3, so columns 1, 2 and 3 are already spoken for. Cross out R1C1, R1C2, R1C3, R2C1, R2C2, R2C3 and 5 more.
  7. Wherever the cat in the Blue region ends up, it rules out R2C6, R3C6 and R3C7. Cross those squares out.
  8. The Teal and Blue regions can only use columns 5 and 6, so columns 5 and 6 are already spoken for. Cross out R1C5, R1C6, R2C5, R9C5, R10C5 and R10C6.
  9. Wherever the cat in column 6 ends up, it rules out R4C7 and R5C7. Cross those squares out.
  10. Rows 1, 2, 3 and 4 can only use the Yellow, Green, Blue and Purple regions, so the Yellow, Green, Blue and Purple regions are already spoken for. Cross out R5C8, R5C9, R5C10, R7C7, R7C8, R7C9 and 3 more.
  11. Wherever the cat in the Purple region ends up, it rules out R1C8, R2C8 and R3C8. Cross those squares out.
  12. Wherever the cat in the Green region ends up, it rules out R1C9. Cross that square out.
  13. Rows 1 and 2 can only use columns 7 and 10, so columns 7 and 10 are already spoken for. Cross out R3C10, R4C10, R7C10, R8C7, R8C10, R9C7 and 3 more.
  14. Wherever the cat in row 7 ends up, it rules out R5C2, R8C1 and R8C2. Cross those squares out.
  15. Wherever the cat in the Grey region ends up, it rules out R9C1 and R10C1. Cross those squares out.
  16. Wherever the cat in the Pink region ends up, it rules out R9C3, R10C8 and R10C9. Cross those squares out.
  17. The Orange region has only one open square left: R9C9. Put a cat there.
  18. The Green region has only one open square left: R1C7. Put a cat there.
  19. The Yellow region has only one open square left: R2C10. Put a cat there.
  20. The Purple region has only one open square left: R4C8. Put a cat there.
  21. The Blue region has only one open square left: R3C5. Put a cat there.
  22. The Teal region has only one open square left: R5C6. Put a cat there.
  23. The Grey region has only one open square left: R7C1. Put a cat there.
  24. The Red region has only one open square left: R8C3. Put a cat there.
  25. The Pink region has only one open square left: R10C2. Put a cat there.

About this puzzle

Where to start: the Brown region is a single square, so its cat is already decided. Its 10 color regions range from 1 square (Brown) to 17 squares. It can be solved in 25 deduction steps using grouped row/column/region deductions.

If a row and a color both have only two open squares and share them, those two lines are locked together -- neither can use squares anywhere else.

This is a variation of the Star Battle family of grid puzzles, sometimes also called Queens-style puzzles, with cats in place of stars.

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