Use LUT for group indexes instead of calculating on-the-fly

Makefile

@@ -24,10 +24,7 @@ CFLAGS += -static
 
 LDFLAGS += -lpthread
 
-# For profiling
-# CFLAGS += -pg
-
-SRC = main.c sud.c solve.c
+SRC = main.c sud.c solve.c lut.c
 OBJ = $(SRC:.c=.o)
 
 default: sudoku eval
@@ -35,16 +32,16 @@ default: sudoku eval
 sudoku: $(OBJ)
 	$(CC) $(CFLAGS) $(LDFLAGS) $(OBJ) -o $@
 
-eval: eval.o
-	$(CC) $(CFLAGS) $(LDFLAGS) eval.o -o $@
-
 clean:
-	rm -f sudoku *.o
+	rm -f sudoku eval genlut *.o lut.c
+
+lut.c: genlut
+	./genlut > $@
 
 eval.o: ds.h
 main.o: sud.h solve.h ds.h
-sud.o: sud.h
-solve.o: solve.h
+sud.o: sud.h lut.h
+solve.o: solve.h lut.h
 
 puzzles: sudoku.csv
 	pv sudoku.csv | tail -n+2 | cut -d, -f1 | tr -d '\n' > $@