Cat Sudoku Level 31 Hint
Find a colored region with only a few safe cells, then compare those cells against the row and column limits.
Cat Sudoku Level 31 Strategy
Medium Level 31 uses a 7x7 board with 7 colored regions. It starts with 2 fixed cats to anchor the solve. Work from the tightest rows and regions before placing a cat.
Cat Sudoku Level 31 Solution
Solution cells: R1C1, R2C5, R3C2, R4C4, R5C6, R6C3, R7C7.