#Peg solitaire algorithm java update#
#Peg solitaire algorithm java series#

The number should fit all the constraints of the problem and to check for it's validity, the function check_validity performs a series of checks. Once an empty cell is found, it is to be filled with a number between 1 and 9. When the cell has the value of 0, it is said to be empty and the function find_empty returns the respective co-ordinates in the form of a tuple with format (row,column). It does this by looping through cells in every row and column. The algorithm starts by finding an empty cell to fill. The empty cells are filled with the number '0' while the rest of the cells are filled with their numbers. The 9 x 9 Sudoku board is stored as 2-dimensional list. Hence, it performs backtracking and results in much lesser computation than the general brute force approach. If the number is proven to be wrong for the position, the algorithm removes this number and tries the next digit. If the number is proven to be in the right position, the algorithm continues by looking for the next empty cell to fill. It then proceeds to check whether this number belongs to the cell and doesn't break the board. The algorithm selects an empty cell and generates a number for this cell. Instead of this, I employed the technique of backtracking to solve the problem. This means that the algorithm is tasked with a task of generating a large number of digits for each board and this results in a combinational explosion as the size of the board increases. This algorithm would be responsible for generating all the board, regardless of whether they are correct or no. To find the solution, one must fill each empty cell with a number between 1 and 9 such that the row, its respective column and subgrid contains exactly one instance of the digit.Ī general approach to solving the puzzle would be to employ a Brute Force algorithm.

The regular Sudoku board is made up of a partially filled 9 x 9 grid of cells. So, backtracking algorithm can be seen as trying to find a path to the solution with small barriers where the problem can backtrack if there is no feasible solution for the problem.

#Peg solitaire algorithm java update#

Otherwise, the program performs an undo operation where the last update is undone, and the next feasible solution for the is found. If the currently found solution holds good with the constraints, then the program continues to the next stage. Each problem has a unique set of constraints which are checked after every step. Unlike Dynamic programming, which looks for the optimal solution, backtracking is used when there are multiple solutions to the problem and all of them need to be found.īacktracking uses a recursive calling function to find a solution in a step-by-step manner.

Backtracking is a technique used for problem solving where the algorithm follows a brute-force approach.