- Introduction
- Sudoku Explained
- How to Think About It
- Getting Started
- A First Approach-
Brute Force - Brute Force in Action
- Improving on Brute Force
- Better Brute Force
- Backtracking Search
- Backtracking with MRV
- Attack of the Samurai
- Strategize
- Backtracking MRV with
Unique Constraint - Backtracking MRV with
Unique Constraint part 2 - Conclusion
How can we improve on Brute Force? Let's take a closer look at something:
One thing you might have noticed, (hopefully because it is highlighted), is that the first two values in the first row contain a conflict. And we certainly won't get to a solution unless that conflict is resolved. But, the solver is going through and mindlessly trying every possible value very very far away from that first conflict.
It seems like it would be better if we checked for conflicts before proceeding down the search tree. After all, if we have a conflict in the first 2 assignments, proceeding with the remaining 62 won't fix that first conflict.