What is backtracking algorithm in Sudoku?

A backtracking algorithm is a recursive algorithm that attempts to solve a given problem by testing all possible paths towards a solution until a solution is found.

How does the backtracking algorithm work?

Backtracking is a technique based on algorithm to solve problem. It uses recursive calling to find the solution by building a solution step by step increasing values with time. It removes the solutions that doesn’t give rise to the solution of the problem based on the constraints given to solve the problem.

Can Sudoku be solved in polynomial time?

No. First of all, solving 4×4 Sudoku is a Polynomial-time problem. Any 4×4 Sudoku puzzle can be solved in less than one trillion years. Since there is a constant upper bound on the time, the problem is O(1), which is polynomial.

How long does it take to solve hard Sudoku?

It can be incredibly challenging to solve a Sudoku puzzle. That’s what makes it fun. It is believed that the average Sudoku player spends approximately 20 minutes solving a typical Sudoku puzzle. For very hard puzzles, that number can be much higher.

What happens when the backtracking algorithm reaches a solution?

What happens when the backtracking algorithm reaches a complete solution? Explanation: When we reach a final solution using a backtracking algorithm, we either stop or continue searching for other possible solutions. Explanation: If a node has a possibility of reaching the final solution, it is called a promising node.

Is Sudoku a NP?

Sudoku is actually what’s called an NP-Complete problem. That is, computer scientists have discovered links between the Sudoku problem and every other NP problem. That means P and NP would be the same group of problems, and that would be the answer to the P versus NP Millennium Prize Problem.

Is Sudoku Solver NP-hard?

Introduction. The generalised Sudoku problem is an NP-complete problem which, effectively, requests a Latin square that satisfies some additional constraints. In addition to the standard requirement that each row and column of the Latin square contains each symbol precisely once, Sudoku also demands block constraints.