Bulldoku solving techniques
Every Bulldoku level in the campaign is solvable by logic only — no guessing. These are the techniques the built-in solver uses.
Naked single
When a row, column, or region has only one cell that can still hold a pup, place it immediately. This opens most easy levels.
Region confinement
If all cells of a color lie in one row (or column), no other region may use that line. Mark X on foreign cells in that row/column.
Line reservation
When N regions’ remaining candidates occupy exactly N rows (or columns), those lines are reserved — eliminate candidates elsewhere on those lines.
Assumption / elimination
On harder boards, trial placement shows that some cell would orphan a region. Mark X instead of guessing.