A sudoku puzzle is made up of nine large blocks, with nine smaller squares inside the large blocks. The goal is to fill each square with a number from one to nine. The number cannot be repeated in any row, column or large square.
The difficulty of the puzzle depends on how many are filled in the starting position, and where they are.
Sudoku Problem Solving
It is never necessary to guess to solve a sudoku puzzle. Each square can be logically figured out by the other filled squares associated with it. The key to solution does not come from reflection or inspiration, but from a systematic approach.
There are two methods of solving the puzzle:
- Find the only square that a particular number can fit in.
- Find the only number that can fit into a particular square.
Step One in Solving Sudoku
When beginning the puzzle, scan the blocks for numbers that appear more than once in the puzzle. If, for instance, the number 1 appears the top left and top middle blocks, look to see if it appears in the top right block. If not, examine the squares in that block to see where it could potentially go.
Eliminate any square that is in line with another number 1, from the top 2 blocks and also from the middle right and bottom right. No square can have two numbers, so eliminate any that squares that already have a number.
Once the 1 is loaded in, use that filled square to help find the number 1 in the rest of the blocks of the puzzle. The puzzle becomes easier has numbers are loaded in. The number the solver loads in is just as good as the initial numbers.
Continuing to Solve the Puzzle
At some point, these easier steps will be exhausted. The next step is to select a block with the most numbers filled in and determine whether any number will work properly into only one square.
When all the blocks have been reviewed, select a row that has the most squares filled and determine whether any number will can only fit into a particular square. When the rows have been reviewed, do the same with the columns.
When this process is completed, and numbers have been added to the puzzle, repeat the steps above. Each number added reduces the empty blocks and increases the chances of deducing another number.
This step by step solution will solve many easy Sudoku puzzles. The logical steps applied above can be used to manage many problems, from puzzles to other decisions that need to be analyzed and solved in a logical manner, using a systematic approach.
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