day 22/part 1: cleanup bash code, remove a loop

2020/day22/ex1.bash

@@ -19,24 +19,21 @@ while read -r line; do
             ;;
     esac
 done
+
 # shellcheck disable=SC2206
-CARDS1=(${cards[0]});
-# shellcheck disable=SC2206
-CARDS2=(${cards[1]})
-while ((${#CARDS1[@]} > 0 && ${#CARDS2[@]})); do
+CARDS1=(${cards[0]}) && CARDS2=(${cards[1]})
+
+while ((${#CARDS1[@]} && ${#CARDS2[@]})); do
     # shellcheck disable=SC2128
     ((CARDS1 > CARDS2)) && CARDS1+=("$CARDS1" "$CARDS2") || CARDS2+=("$CARDS2" "$CARDS1")
     CARDS1=("${CARDS1[@]:1}")
     CARDS2=("${CARDS2[@]:1}")
 done
-cards=()
+
+declare -i n=$((${#CARDS1[@]}+${#CARDS2[@]})) res=0 i
+
 for i in "${CARDS1[@]}" "${CARDS2[@]}"; do
-    cards=("$i" "${cards[@]}")
-done
-n=1
-res=0
-for i in "${cards[@]}"; do
-    ((res+=n*i, n++))
+    ((res+=n*i, n--))
 done
 printf "%s: res=%d\n" "$CMD" "$res"
 exit 0