Re: multiple solutions to 1-Oct-14, 4x4 Difficult?

Thanks for letting me know. I'm as far as having figured out that this is a bug

introduced in a more recent version of my solver

I ran an old version of the solver (from July 2010 (!)) on this puzzle, and it found

all five solutions.

Edit: found the bug, a fix for a problem which caused it to not be able to solve puzzles

larger than 15x15 (which I needed for the new book, which has one 17x17 puzzle) introduced

a new bug for puzzles with cages larger than 5 cells

Challenge to you all: how to modify the current puzzle so only this solution:

**Code:**

3 4 1 2

4 2 3 1

2 1 4 3

1 3 2 4

is valid??

Edit #2: I changed the puzzle a bit so the above is a single valid solution.

Patrick