How do you cross hatch in Sudoku?

You can use cross-hatching as before with the two 1s to eliminate five of the squares in the middle-left box. That means that the 1 in this box can only be in the middle column. Using that and the 1 from the top box means that in the lower box the 1 must be in the left-hand column, in this case the bottom-left square.

What is the best algorithm to solve Sudoku?

backtracking algorithm
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.

What are the 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.

How do you find hidden pairs in Sudoku?

Hidden Pairs can be found easily using pencil marks. Take a look at the sudoku: After a few singles pencil marks were applied for candidates 4 and 8. The Hidden Pair in r3c46 becomes immediately visible. No other candidate can go into one of those cells.

Is there a method to solving Sudoku?

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.” If you’re looking to …

What is brute force in Sudoku?

A brute force algorithm visits the empty cells in some order, filling in digits sequentially, or backtracking when the number is found to be not valid. Briefly, a program would solve a puzzle by placing the digit “1” in the first cell and checking if it is allowed to be there.