rename repo, subdir for yearly challenges

2020/day14/ex2.bash

@@ -0,0 +1,61 @@
+#!/bin/bash
+#
+# ex2.bash: Advent2020 game, day 14/game 2.
+
+CMD=${0##*/}
+shopt -s extglob
+declare -A mem
+declare -i pos exp lenmask
+declare ORMASK ANDMASK
+declare -a xlist
+
+function applymask() {
+	local -i curmem val mask
+	if (($# < 3)); then
+		mem[$1]=$2
+		return
+	fi
+
+	curmem="$1"
+	val="$2"
+	mask="$3"
+	shift 3
+	applymask "$curmem" "$val" $*
+	applymask $((curmem+mask)) "$val" $*
+}
+
+while read -r line; do
+	line=${line// /}
+
+	if [[ $line =~ ^mask ]]; then
+		eval "$line"
+		ORMASK=2\#${mask//X/0}
+		ANDMASK=2\#${mask//0/1}
+		ANDMASK=${ANDMASK//X/0}
+		lenmask=${#mask}
+		xlist=()
+		exp=1
+		for ((i=1; i<=lenmask; ++i)); do
+			c=${mask: -i:1}
+			if [[ "$c" == "X" ]]; then
+				xlist+=("$exp")
+			fi
+			((exp<<=1))
+		done
+	else
+		[[ $line =~ ^.*\[([0-9]+)\][^0-9]*([0-9]+)$ ]]
+		pos=${BASH_REMATCH[1]}
+		val=${BASH_REMATCH[2]}
+		((pos |= ORMASK))
+		((pos &= ANDMASK))
+		applymask "$pos" "$val" ${xlist[*]}
+
+	fi
+
+done
+SUM=0
+for i in ${!mem[@]}; do
+	((SUM+=${mem[$i]}))
+done
+printf "%s : res=%d\n" "$CMD" "$SUM"
+exit 0