What is the minimum number of clues for 4x4 Sudoku?

For 4x4 Sudoku of order n=2, the minimum number of starting clues is 4. For 9x9 Sudoku of order n=3, the minimum number of starting clues is 17.

What is the minimum number of clues problem in Sudoku?

Puzzles must have at least 17 clues to have a valid solution.

How many solutions does a 4x4 Sudoku have?

Then they should show that the top row can be rearranged in 4! = 24 different ways. Hence the total possible 4x4 Sudoku Latin squares is 16 x 24 = 384.

How do you solve a 4x4 Sudoku puzzle?

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).

17 and Sudoku Clues - Numberphile

Is it not allowed to repeat numbers in the diagonal in the 4x4 Sudoku game?

Rules for Solving Diagonal Sudoku

You can't repeat any of the numbers in a single row. The numbers 1–9 must appear exactly once in each column. The 9 vertical columns have 9 cells each, so every number will only fit once.

What is Sudoku 4 cell rule?

Rules of Quadruple Sudoku

The object of the puzzle is to fill in the whole 9x9 grid with numbers 1 through 9 (one number per cell) so that each row, each column, and each of the nine 3x3 boxes contains all the nine different numbers 1 through 9. The clues are in the form of sets of four special clue-numbers.

Can there be 2 solutions to a Sudoku puzzle?

A well-formed Sudoku puzzle is one that has a unique solution. A Sudoku puzzle can have more than one solution, but in this case the kind of logical reasoning we described while discussing solving strategies may fall short.

Is there a trick to solving Sudoku puzzles?

There are more than a few techniques to solve a Sudoku puzzle, but per Conceptis Puzzles, the easiest way to a Sudoku solution is to, “Scan rows and columns within each triple-box area, eliminating numbers or squares and finding situations where only a single number can fit into a single square.”

How do you count the number of solutions in a Sudoku?

If there are no errors and the board is full, then there is one solution. If there are no errors but the board isn't full, then pick the earliest empty cell, and sum the number of solutions for the boards which contain 1, 2, ..., 9 in that cell.

What is the rule of 3 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.

What is the lowest common multiple Sudoku?

Rules of LCM Sudoku

The numbers at the end of the rows and at the bottom of the columns are the Lowest Common Multiples (LCM) of the letters in that row. The LCM of the variables b, w, m and c in the fourth row is 504. As an example, the LCM of 8, 9, 6, 4, 2, 5 and 7 is 2520.

Can all Sudoku puzzles be solved without guessing?

The short answer is yes. Every proper Sudoku puzzle can be solved without ever having to make a guess. Another way of thinking about it is that every Sudoku puzzle can be solved logically. Even though it may require highly complicated solving techniques you're not familiar with.

What is the rule of two in Sudoku?

The game of Sudoku consists of a grid of nine rows and nine columns subdivided into nine 3x3 subgrids. It has two basic rules: Each column, each row, and each box (3x3 subgrid) must have the numbers 1 to 9. No column, row or box can have two squares with the same number.

How many possibilities are there for a 4x4 cube?

The 4x4x4 Rubik's cube (called the Master Cube, or Rubik's Revenge – not sure who he was avenging, I must say) has 7 401 196 841 564 901 869 874 093 974 498 574 336 000 000 000 combinations (that is, 7.4 quattuordecillion, if you really wanted to know).

What is the easiest 4x4 parity algorithm?

OLL Parity Algorithm 1:

This algorithm is the easiest to execute. It flips the two edge pieces as well as the corners. It also moves other edge pieces in the top layer. If your focus is speedsolving the 4x4 then this is the recommended algorithm.

What is the L rule in Sudoku?

The L pattern exists when there is a wall that has one populated cell adjacent to it. The wall and the adjacent cell must be in the same box.

What are the 159 rules in Sudoku?

Normal sudoku rules apply: Each row, column, and region indicated by thick borders in the grid must contain the digits 1 to 9 once each. 159: Digits in column 1 indicate the column in which the digit 1 appears in that row (e.g. if r4c1 is a 6, r4c6 is a 1).

Can the same number be in the same spot in Sudoku?

Sudoku puzzles cannot have the same number twice in any row, column or box (container). You can take advantage of this by using deduction to determine (1) which numbers are missing, and (2) where the missing numbers go.

What is the maximum number of Sudoku combinations?

There are exactly 6, 670, 903, 752, 021, 072, 936, 960 possible solutions to Sudoku (about 10^21) . That's far more than can be checked in a reasonable period of time.

What is the magic number in Sudoku?

Now Gary McGuire, a mathematician at University College Dublin, has come up with what he says is a proof that finds the minimum number of clues, or starting digits, needed to complete the game is 17.