Sudoku (数独 sūdoku, digit-single) – is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid (also called “boxes”, “blocks”, or “regions”) contains all of the digits from 1 to 9. Killer Sudoku puzzles include all the rules of regular Sudoku but add in dashed-line ‘cages’ which must sum to given values. Killer Sudoku is also sometimes known as Sumdoku, Mathdoku or Addoku. The name ‘Killer’ Sudoku arises because of the wicked twist on the…