updatewhe.blogg.se - Correct sudoku example

Note: Not every time you add a new number to the grid will reveal a cell. This only leaves the bottom right cell of the top left box available for the 2. Likewise, the two given 2s in top middle and right boxes also rule out the first two rows of the top left box from containing a 2.

This is because the 2 we added in step 3 rules out the 2 from appearing in the middle column of the box. That is, squares where only one number can go without breaking any rules.įor instance, only the number 2 can go into the square highlighted below. When you start a new Sudoku puzzle, some squares will already be filled with numbers.īased on how difficult the puzzle is, these numbers will ‘lock in’ specific numbers to specific squares. Step 3: Find squares that can only be one number In other words, no number can be repeated in any 3×3 box, row, or column. Once the puzzle is solved, this means that every row, column, and 3×3 box will contain every number from 1 to 9 exactly once.

Each horizontal row can only contain each number from 1 to 9 once.

Each vertical column can only contain each number from 1 to 9 once.

Each 3×3 box can only contain each number from 1 to 9 once.

Only the numbers from 1 through to 9 can be used.

Every square has to contain a single number.

Sudoku is a puzzle based on a small number of very simple rules: In total there are 81 squares on a Sudoku grid and when the puzzle is completed each square will contain exactly one number.