Day 17 part 2, bash version (and retrofit to part 1)

day17/ex2.bash

@@ -0,0 +1,74 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 17/game 1.
+
+CMD=${0##*/}
+#shopt -s extglob
+
+declare -A life=()
+declare -i x=-1 y=-1 z=-1 w=-1 res=0
+declare -i loops=6
+
+function run_cycle () {
+	local -i x y z w x1 y1 z1 w1 v
+	local -A lifetmp=()
+	local -a values
+
+
+	for k in "${!life[@]}"; do
+		# shellcheck disable=SC2206
+		values=(${k//-/ })
+		x=${values[0]}
+		y=${values[1]}
+		z=${values[2]}
+		w=${values[3]}
+
+		for ((x1=x-1; x1<x+2; ++x1)); do
+			for ((y1=y-1; y1<y+2; ++y1)); do
+				for ((z1=z-1; z1<z+2; ++z1)); do
+					for ((w1=w-1; w1<w+2; ++w1)); do
+						if ((x1!=x || y1!=y || z1!=z || w1!=w)); then
+							((++lifetmp[$x1-$y1-$z1-$w1]))
+						fi
+					done
+				done
+			done
+		done
+	done
+
+	# clean elements with no neighbors
+	for k in "${!life[@]}"; do
+		if [[ ! -v lifetmp[$k] ]]; then
+			unset "life[$k]"
+		fi
+	done
+	for k in "${!lifetmp[@]}"; do
+		v=${lifetmp[$k]}
+
+		if [[ -v life[$k] ]]; then
+			(( v!=2 && v!=3 )) && unset "life[$k]"
+		else
+			(( v==3 )) && life[$k]="#"
+		fi
+	done
+}
+
+x=$loops; y=$loops; z=$loops; w=$loops
+while read -r line; do
+	for ((j=0; j<${#line}; ++j)); do
+		((curx=x+j))
+		c=${line:j:1}
+		if [[ $c == "#" ]]; then
+			life[$curx-$y-$z-$w]=$c
+		fi
+	done
+	((y++))
+done
+for ((i=0; i<6; ++i)); do
+	run_cycle
+done
+res=${#life[@]}
+
+printf "%s : res=%d\n" "$CMD" "$res"
+
+exit 0