rename repo, subdir for yearly challenges

2020/day05/ex2.bash

@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# ex2.bash: Advent2020 game, day 5/game 2.
+
+CMD=${0##*/}
+shopt -s extglob
+declare -a seats
+
+function rownum() {
+	local val=${1%%???}
+	val=${val//F/0}
+	val=${val//B/1}
+	echo $((2#$val))
+}
+function colnum() {
+	local val=${1##???????}
+	val=${val//L/0}
+	val=${val//R/1}
+	echo $((2#$val))
+}
+
+declare -i lines=0 max=0 row col res next
+
+while read -r line; do
+	((lines++))
+	row=$(rownum "$line")
+	col=$(colnum "$line")
+	res=$((row * 8 + col))
+	seats[$res]=1
+	#((max < res)) && max=$res
+	#echo "row=$row col=$col res=$res"
+done
+
+for seat in ${!seats[@]}; do
+	((next=seat+1))
+	[[ -v seats[$next] ]] || break
+done
+printf "%s : lines=%d seat=%d\n" "$CMD" "$lines" "$next"
+
+exit 0