bash regex basic simplification (50% time/cpu savings)

day19/Makefile

@@ -1,4 +1,5 @@
-INPUT := INPUT.txt
+INPUT1 := INPUT-part1.txt
+INPUT2 := INPUT-part2.txt
 SHELL := /bin/bash
 CFLAGS := -w -g
 #CFLAGS := -w -g -pg
@@ -16,12 +17,13 @@ output:
 compile: ex1-c ex2-c
 
 ex1:
-	@$(TIME) ex1.bash < $(INPUT) 2>&1
-	@#$(TIME) ex1-c 2020 < $(INPUT) 2>&1
+	@$(TIME) ex1.bash < $(INPUT1) 2>&1
+	@$(TIME) ex1-v2.bash < $(INPUT1) 2>&1
+	@#$(TIME) ex1-c 2020 < $(INPUT1) 2>&1
 
 ex2:
-	@$(TIME) ex2.bash < $(INPUT) 2>&1
-	@#$(TIME) ex1-c 30000000 < $(INPUT) 2>&1
+	@$(TIME) ex2.bash < $(INPUT2) 2>&1
+	@#$(TIME) ex1-c 30000000 < $(INPUT2) 2>&1
 
 clean:
 	@rm -f ex1-c ex2-c core

day19/ex1.bash

@@ -29,7 +29,11 @@ function buildtree {
         else
             if [[ ! -v MATCH[$arg] ]]; then
                 buildtree "$((prof+1))" "$name" "${RULE[$arg]}"
-                MATCH[$arg]="(${!name})"
+                if [[ ${!name} =~ ^.$ ]] ; then
+                    MATCH[$arg]="${!name}"
+                else
+                    MATCH[$arg]="(${!name})"
+                fi
             fi
             res+=${MATCH[$arg]}
         fi