Sudoku evil is a programming problem that has been discussed extensively in recent years. It’s a new type of challenge that was created because of our need for more creativity. For many, solving a sudoku puzzle can be as hard and frustrating as trying to solve a cube. For others, it is an easy leisure activity that they enjoy doing on their train ride or lunch.
To solve Sudoku Evil, you need to understand how to use the techniques described below;
Scanning
Scanning involves looking for an area on the board that may be used as part of your solution. If you find an area that can be used as part of your solution, then you need to see if other players can use any other sites on the board.
Forcing chains
One way to solve Sudoku Evil is by using the forcing chains technique. This technique involves looking for cells that are related by an unbroken path of numbers and assigning values to them until only one possible solution remains. Once you have found all the forcing chains in your puzzle, you can connect them into groups and assign values to each group until only one possible solution remains.
Crosshatching
Crosshatching is a technique used to determine whether a cell can be filled in. You draw lines across the cell and see if it forms a rectangle or square. If it does not create a rectangle, then the cell cannot be filled in because eight other cells are already touching it on either side. This technique will prove useful when solving large chunks of your puzzle at once and when setting up clues for later use.
Sub-group exclusion
Solving a Sudoku puzzle is finding the candidate solutions for each digit. This can be done by looking at the number of possible values for each cell and then trying to eliminate those that are impossible using the constraints of the rest of the puzzle. For example, if cell (1, 1) has 2 possible values, and there is only one other cell with 2 possible values, then we know that this cell must be 2.
Unary minimization
Once we have identified which cells are definitely not candidates, we can look at all possible ways of assigning values to those cells. The fewer numbers used in the assignment, the more likely it is to be correct, assuming there are no other constraints. For example, if only one value can go into the cell (1, 1), then only one solution will work for this cell. If two values get into this cell, then any of these two solutions will work. If three values, then any one of these three will work.
The chain matrix method
This method is usually used when only one or two remaining candidates for each cell in the puzzle. The Chain Matrix Method involves creating chains of logical deductions from clues given by intersecting pairs of cells or chains. Sometimes this method may involve making chains with three or more cells if many intersecting pairs are available within the puzzle. Once all logical deductions have been made from each chain, then all other candidates within each chain are eliminated, leaving only one candidate remaining per cell in the puzzle.
The X-wing
It is one of the most common techniques used when solving a Sudoku puzzle. The X-wing is used to find two numbers that can be placed in a row, column, or box. When you have identified two numbers in a row, column, or box that are impossible together, you can place them together as one number. This will help reduce the number of candidates for other cells and make it easier for you to solve the puzzle.
Swordfish technique
The swordfish technique is used to solve cages with three cells in a row or column or both containing only one number each. It works because if you find a cage like this and fill it in with one number, then all other possible placements of that number become invalid and disappear from your grid.
Backtracking
This technique is used to find values for cells in a chain that cannot be reached by any other cell. The idea is that we can permanently eliminate the numbers that appear in a chain, but we cannot do this if there are two chains with the same set of numbers. In order to solve these chains, we need to find another chain with a different set of numbers so that we can get rid of some of its numbers as well. Using backtracking, you can find all possible places where two chains connect and then solve both chains at once.
XY-Wing variation
It is a more advanced technique used to solve Sudoku puzzles by eliminating possible options for cells that share an edge with another cell. The X stands for any number in the same row, column, or box, as the number being tested stands for any number in the same row, column, or box as another test number, not necessarily the same one. This can be applied to individual cells or entire columns, rows, and boxes of cells.
Unique rectangle type 2
This is done by looking for large empty areas on your grid that contain all of the numbers 1 through 9 and are not connected to any other large empty area that contains all of these same numbers. These large empty areas will be surrounded by smaller empty regions that contain all of these same numbers as well as some other numbers from outside of these large empty areas.
Conclusion
This will clear some things up and help you out in tackling evil Sudoku. It’s easy once you know the basics, but like any puzzle, it can be a bit challenging before you get familiar with it. A good way to do that is to sit down with a piece of paper and work out the steps yourself so you can get an idea about how it works.
