2015/advent6.sh

   1 mapfile -t list < <(sed 's/turn //; s/through //; s/,/ /g')
   2 echo "parsed ${#list[*]} instructions"
   3 count=0
   4 for row in {0..999}; do
   5     echo "processing row $row"
   6     for col in {0..999}; do
   7         line[$col]=0
   8     done
   9     # printf " inst 000"
  10     for ((i = 0; i < ${#list[*]}; i++)); do
  11         # printf '\b\b\b%3d' $i
  12         read inst x1 y1 x2 y2 <<< ${list[$i]}
  13         if [[ $row -lt $y1 || $row -gt $y2 ]]; then
  14             # echo " no-op for inst $i on row $row"
  15             continue;
  16         fi
  17         # echo " $i: running operation $inst over $((x2-x1+1)) cells"
  18         pos=$x1
  19         while [[ $pos -le $x2 ]]; do
  20             if [[ $part1 ]]; then
  21                 case $inst in
  22                     on) line[$pos]=1 ;;
  23                     off) line[$pos]=0 ;;
  24                     toggle) line[$pos]=$((1-${line[$pos]})) ;;
  25                     *) echo oops; exit 2 ;;
  26                 esac
  27             else
  28                 case $inst in
  29                     on) line[$pos]=$((${line[$pos]}+1)) ;;
  30                     off) line[$pos]=$((${line[$pos]}?${line[$pos]}-1:0)) ;;
  31                     toggle) line[$pos]=$((${line[$pos]}+2)) ;;
  32                     *) echo oops; exit 2 ;;
  33                 esac
  34             fi
  35             pos=$((pos + 1))
  36         done
  37     done
  38     subcount=$(( $(echo ${line[*]} | tr ' ' +) ))
  39     # echo
  40     printf "row $row adds $subcount\n"
  41     count=$((count + subcount))
  42 done
  43 echo "final count $count"