[Gunax]

Internally, do contraint solvers just do brute force?

It's interesting how powerful contraint solvers are (Ive never used one).

But actually all of these problems are fairly simple if we allow brute force solutions. They just become stacked loops.

[cerved]

No. They use sophisticated algorithms called propagators to prune the invalid solutions from the domains of possible solutions in conjunction with a search strategy, like branch and bound