+ /* If we're the solver we need the grid all to be definitively
+ * black or definitively white (i.e. circled) otherwise the solver
+ * has found an ambiguous grid. */
+ if (flags & CC_MUST_FILL) {
+ for (i = 0; i < state->n; i++) {
+ if (!(state->flags[i] & F_BLACK) && !(state->flags[i] & F_CIRCLE))
+ error += 1;
+ }
+ }
+