Day 22 part 1 (bash)

2020/day22/ex1.bash

@@ -0,0 +1,42 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 22/game 1.
+
+CMD=${0##*/}
+shopt -s extglob
+set -o noglob
+
+declare -a cards=() CARDS1=() CARDS2=()
+declare -i count=-1
+
+while read -r line; do
+    case ${line:0:1} in
+        P*)
+            ((count++))
+            ;;
+        [1-9]*)
+            cards[$count]+=" $line"
+            ;;
+    esac
+done
+# shellcheck disable=SC2206
+CARDS1=(${cards[0]});
+# shellcheck disable=SC2206
+CARDS2=(${cards[1]})
+while ((${#CARDS1[@]} > 0 && ${#CARDS2[@]})); do
+    # shellcheck disable=SC2128
+    ((CARDS1 > CARDS2)) && CARDS1+=("$CARDS1" "$CARDS2") || CARDS2+=("$CARDS2" "$CARDS1")
+    CARDS1=("${CARDS1[@]:1}")
+    CARDS2=("${CARDS2[@]:1}")
+done
+cards=()
+for i in "${CARDS1[@]}" "${CARDS2[@]}"; do
+    cards=("$i" "${cards[@]}")
+done
+n=1
+res=0
+for i in "${cards[@]}"; do
+    ((res+=n*i, n++))
+done
+printf "%s: res=%d\n" "$CMD" "$res"
+exit 0