| Naive |
Look for the next open cell (linearly), find and place the next non-conflicting
guess, then go on, backtrack when there are no valid guesses for a cell |
| Smarter-1 |
Same as Naive, but after filling a cell with a guess, find and fill all
cells that have forced answers because of the guess just applied.
Continue to find forced cells until no more can be found. Then go
to next open cell |
| Smarter-2 |
Instead of the next open cell, find one that has the smallest number
of guesses. After placing a guess in a Cell, remove that guess
from all open cells in the neighborhood of the Cell. That may
force some neighbors. For each neighbor forced, remove its guess
from all of its neighbors, etc. Continue until no more changes. |