ondine/solving-sudoku

Writing a Sudoku Solver

Sudoku is a puzzle game with one rule: Each row, column, and section can contain only 1 of a given number.

Step 1: Program Yourself

Take ~5 minutes and play a game. Notice the steps you take as you work through it. Then, in 40 words or less, outline a "program" telling you how to solve sudoku.

Consider:

• What questions do you ask while working through the puzzle?
• What do you do over and over again?

As a person, it's easy to follow high level instructions like "if the column, row or section has a 5 disqualify it as a possible value."

Computers, on the other hand, need more detailed (low-level) instructions. The ability to break down high level instructions to lower level instructions is one of the most useful skills of being a programmer.

Take a monent to flesh out your outline to include more detail.

Think about:

• What data is needed in which parts of the outline?
• Are there any branches of the outline which are independent of other parts?
• Which parts of the outline had surprisingly more (or less) instructions behind an "obvious-to-human" instruction?

Step 2: Program The Computer

Now that you have a rough draft it's time to start translating this into true-blue code.

open sudoku.rb in sublime, and start converting your outline into code. Run ruby sudoku.rb frequently to see how close you're getting.