I create the solutions for my killer sudoku puzzles using the C program which produces my standard 9x9 sudoku puzzles. I then create the puzzles by trial and error using Andrew Stuart's Killer Sudoku Solver This is fairly labour intensive so each one takes an hour or so to make.
Usual sudoku rules apply i.e. each row, column and 3x3 mini-grid must have all of the numbers 1 to 9 exactly once. The puzzle is also divided into smaller areas called cages, which are surrounded by dashed lines. Numbers are not repeated within a cage. The number in the top left hand corner of each cage shows the sum of the numbers in that cage:
Killer sudoku solver
See answer
