## What is the best algorithm to solve Sudoku?

the backtracking algorithm

Table of Contents

The Algorithm

One algorithm to solve Sudoku puzzles is the backtracking algorithm. Essentially, you keep trying numbers in empty spots until there aren’t any that are possible, then you backtrack and try different numbers in the previous slots.

## Are there algorithms to solve Sudoku?

The interesting fact about Sudoku is that it is a trivial puzzle to solve. The reason it is trivial to solve is that an algorithm exists for Sudoku solutions. The algorithm is a tree-based search algorithm based on backtracking in a tree until a solution is found.

**How do you write an algorithm for Sudoku?**

The first step is easy, list out all possible numbers in each cell. If you have used an app to play Sudoku, there should already be a function allowing you to write down some possible numbers in a cell. In the first step of the algorithm, for each cell, you follow the rules and write down all possible numbers.

**What will be the time complexity of 16 * 16 suduko if it is having M empty spaces using backtracking?**

4)Time and Space Complexity

The backtracking algorithm takes O(9m) time complexity in the worst case since for every unfilled cell there are 9 possibilites to explore and there are m unfilled cells in the sudoku. For Brute force approach: Worst Case Time Complexity: O(9m)

### What is the fastest time to solve a Sudoku?

1 minute 23.93 seconds

According to Guinness World Records, the fastest time to complete a “Very Easy” difficulty Sudoku puzzle was 1 minute 23.93 seconds. The record was set on May 20, 2006 by Thomas Snyder, an American Sudoku champion. How does Thomas Snyder solve Sudoku puzzles so fast, and how can you solve Sudoku puzzles faster?

### Is Sudoku all logic?

Sudoku does not require guessing. In fact, when solving Sudoku puzzles, you’re better off NOT guessing at all. Sudoku is a logic puzzle, using the power of simple deductive reasoning and process of elimination to fill in the gaps in the grid. Simply put – you don’t need luck to play Sudoku.

**Does Sudoku have only one solution?**

A properly formulated Sudoku puzzle has a unique solution. One can assume that a given puzzle actually is properly formulated, and use that in the reasoning, to exclude branches that would not lead to a unique solution.

**Is coding like Sudoku?**

Many people talk about programming as more akin to math, but I like to compare it to Sudoku puzzles. Similar to programming, Sudoku puzzles use numbers, but that doesn’t make it a math puzzle because letters can be substituted just as easily. It’s a logic puzzle with certain rules.

## Is Sudoku always 9 * 9?

In classic Sudoku, 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”) contain all of the digits from 1 to 9.

## What is the time complexity of Sudoku solver?

Time Complexity: O(n ^ m) where n is the number of possibilities for each square (i.e., 9 in classic Sudoku) and m is the number of spaces that are blank.

**Does Sudoku increase IQ?**

Practising a game like sudoku or using a brain training app might make you better at it but it won’t boost your IQ or general brain power, a study claims. And instead, researchers suggest people exercise more, socialise and make sure they get enough sleep if they want their mind to be sharper.

**Is Sudoku good for brain?**

Sudoku is a good cognitively stimulating leisure-time activity [2]. Sudoku requires attention of the subject to analyze the grids and fill in the numbers; basically it requires no math but is based on logic [1].

### What is the 45 rule in Sudoku?

The 45 rule is a basic solving-technique in Killer Sudoku. Each house (row, column, nonet) must add to 45 (the sum of the digits 1 through 9).

### Can a Sudoku have 2 solutions?

The short answer is no. Any proper Sudoku puzzle should only have one unique solution that can be found through logical deduction without the need for guessing.

**Can Sudoku increase IQ?**

**Can a Sudoku be unsolvable?**

The square Ei must therefore take a 2 and after that difficult step the puzzle can be solved with no more big problems. These hard puzzles may seem ‘unsolvable’ to all but the committed Sudoku expert. We sometimes receive puzzles that our users consider ‘unsolvable’, but with a bit of study they can usually be solved.

## Is Sudoku good for logic?

Sudoku boosts logical thinking.

It requires absolutely no arithmetic skills, but it does require logical reasoning. As you learn to arrange the numbers correctly, your logical thinking skills improve.

## What are the 3 rules of Sudoku?

Sudoku Rules

- Rule 1 – Each row must contain the numbers from 1 to 9, without repetitions.
- Rule 2 – Each column must contain the numbers from 1 to 9, without repetitions.
- Rule 3 – The digits can only occur once per block (nonet)
- Rule 4 – The sum of every single row, column and nonet must equal 45.

**Which data structure is used in Sudoku?**

The puzzle of sudoku is one consisting of a nine by nine grid of squares and the grid is divided up into three by three grids of three by three squares. Each row, column and sub-grid can only contain one instance of the digits 1 through 9 and some entries are given.

**Is Sudoku good for mental health?**

Sudoku requires attention of the subject to analyze the grids and fill in the numbers; basically it requires no math but is based on logic [1]. Solving puzzles has long been thought to keep the brain healthy [2] and has been shown to delay the onset of dementia [3].

### Is Sudoku harder than chess?

A chess problem is much more complicated than a Sudoku, because the number of possibilities could be astronomical. Such problems are generally infeasible unless White can force checkmate in a few moves.

### What kind of person plays Sudoku?

Some of the best Sudoku players seem to be exceptionally good at “switching off their minds” to the outside world and being able to focus for hours on solving Sudoku puzzles. Sudoku is a game that requires concentration.

**What is a hidden triple in Sudoku?**

If three candidates can be found in only the same three Cells of a region (Row, Column or Square), then one of these candidates is the solution for the first of these Cells, a second one is the solution for the second Cell and the last candidate is the solution for the third Cell.

**Is there a pattern to Sudoku?**

The essence of the standard sudoku pattern is threefold: (a) a 9-by-9 grid of squares is divided into nine square sub-grids; (b) a set of nine distinct symbols is used, be they digits, letters, colors or shapes; (c) each row, each column and each sub-grid must contain each of the symbols exactly once.

## What is the hardest level of Sudoku?

Techniques and Costs

Level | Lowest Difficulty Score | Highest Difficulty Score |
---|---|---|

Medium | 5300 | 6900 |

Tricky | 6500 | 9300 |

Fiendish | 8300 | 14000 |

Diabolical | 11000 | 25000 |