A Sudoku solver written in TypeScript. The solver applies optimized backtracking for solving puzzles. If you want to see the solver in action, you can visit this website.
The solver expects as argument a 9x9 number
array where an entry is either an integer between 1
and 9
(in case the entry is known), or -1
(in case the entry is unknown and needs to be calculated by the solver).
Currently, the solver provides the following functions:
-
solveSudoku(sudoku: number[][])
: Solves a Sudoku puzzle. The function returns an array[solvable: boolean, solution: number[][]]
. Here,solvable
indicates whether the Sudoku puzzle is solvable or not, andsolution
is a valid solution for the Sudoku puzzle (if the puzzle is solvable). -
nextNumber(sudoku: number[][])
: Calculates the next number for a Sudoku puzzle. The function returns whether the puzzle isSolvable, and it returns the row, the column, and the entry itself for the next number. In particular, the function returns the entry for the field with the fewest number of possible entries. For instance, if there is a field with 7 possible entries and another field with only 2 possible entries, a correct entry for the latter is returned. NOTE: If the Sudoku puzzle is already completely solved, this function returns value -1 for row, column, and entry.
Note, that the solver currently does not validate Sudoku puzzles. Instead, the solver expects the following properties for inputs:
- The input is a 9x9
number[][]
array where each entry is an integer between1
and9
, or-1
(see above). - Each row contains every value between
1
and9
at most once. - Each column contains every value between
1
and9
at most once. - Each 3x3 box contains every value between
1
and9
at most once.