A 10x10 board rated fiendish, level 300 of 300. Catdoku levels are identical for every player, so this solution always matches the board in your game.
The level 300 board
Place one cat in every row, every column and every colored patch. No two cats may touch, not even diagonally.
Level 300 answer
Row 1: column 9, in the yellow patch
Row 2: column 5, in the sky patch
Row 3: column 7, in the rose patch
Row 4: column 3, in the mint patch
Row 5: column 1, in the lilac patch
Row 6: column 6, in the peach patch
Row 7: column 2, in the aqua patch
Row 8: column 8, in the coral patch
Row 9: column 10, in the lime patch
Row 10: column 4, in the periwinkle patch
How to solve level 300, step by step
After every placed cat, cross out the rest of its row, its column, its patch and the four corner squares around it. The steps below assume you do (the in-game auto-paws assist does it for you).
Every free square of the yellow patch sits in row 1, so the yellow cat must come from there and the rest of row 1 can be crossed out. Every free square of the lilac patch sits in column 1, so the lilac cat must come from there and the rest of column 1 can be crossed out. A cat at row 2, column 9 would leave row 1 with no home for its cat, so cross that square out. A cat at row 2, column 10 would leave row 1 with no home for its cat, so cross that square out. A cat at row 3, column 5 would leave the sky patch with no home for its cat, so cross that square out. A cat at row 4, column 2 would leave column 1 with no home for its cat, so cross that square out. A cat at row 5, column 2 would leave column 1 with no home for its cat, so cross that square out. A cat at row 9, column 3 would leave the periwinkle patch with no home for its cat, so cross that square out. The sky, rose, mint and lilac patches all squeeze into rows 2, 3, 4 and 5, so those rows are reserved for them; every other square there can be crossed out. The yellow and lime patches all squeeze into columns 9 and 10, so those columns are reserved for them; every other square there can be crossed out. Cat 1 of 10: the only free square left in row 5 is column 1, so the cat goes there.
A cat at row 3, column 3 would leave row 4 with no home for its cat, so cross that square out. A cat at row 3, column 4 would leave row 4 with no home for its cat, so cross that square out. A cat at row 7, column 4 would leave row 6 with no home for its cat, so cross that square out. The mint and aqua patches all squeeze into columns 2 and 3, so those columns are reserved for them; every other square there can be crossed out. Cat 2 of 10: the periwinkle patch is down to a single free square at row 10, column 4, so its cat settles there.
Cat 3 of 10: the only free square left in row 4 is column 3, so the cat goes there.
Cat 4 of 10: the aqua patch is down to a single free square at row 7, column 2, so its cat settles there.
Every free square of the sky patch sits in row 2, so the sky cat must come from there and the rest of row 2 can be crossed out. Every free square of the coral patch sits in column 8, so the coral cat must come from there and the rest of column 8 can be crossed out. Row 6 only has free squares inside the peach patch, so that patch's cat is spoken for and its squares outside the line can be crossed out. A cat at row 2, column 6 would leave row 3 with no home for its cat, so cross that square out. Cat 5 of 10: the sky patch is down to a single free square at row 2, column 5, so its cat settles there.
Cat 6 of 10: the rose patch is down to a single free square at row 3, column 7, so its cat settles there.
Cat 7 of 10: the peach patch is down to a single free square at row 6, column 6, so its cat settles there.
A cat at row 8, column 9 would leave row 9 with no home for its cat, so cross that square out. Cat 8 of 10: the only free square left in row 8 is column 8, so the cat goes there.
Cat 9 of 10: the lime patch is down to a single free square at row 9, column 10, so its cat settles there.
Cat 10 of 10: the yellow patch is down to a single free square at row 1, column 9, so its cat settles there.