 There are several computer algorithms that will solve most 9×9 puzzles (=9) in fractions of a second, but combinatorial explosion occurs as increases, creating limits to the properties of Sudokus that can be constructed, analyzed, and solved as increases.Some hobbyists have developed computer programs that will solve Sudoku puzzles using a backtracking algorithm, which is a type of brute force search.Backtracking is a "depth-first" search (in contrast to a "breadth-first" search), because it will completely explore one branch to a possible solution before moving to another branch.