A few years ago I gave a shot and tried a few levels by hand and thought about how to solve it programatically, but quickly lost interesst. Last weekend I gave it another shot and a few moments ago just reached 643.
I solved it with a very straight forward gauss elimination and didn't optimize it very well ^^ At about level 300 I rewrote small parts of the program (transitioned from bool[] to BitArray). After that my estimates showed that solving all 643 would only take about a day on my machine so I didn't bother optimizing it any further.
Solving the last puzzle took my machine/algorithm about 12 min and reading through the comments for this puzzle I'm very impressed that some people (I'm looking at you @tails ^^) managed to solve the last one in about 20 seconds on a celeron CPU years ago.
Still works in 2020 :-)
Re: Still works in 2020 :-)
Still works in 2023 