2015/advent3.sh

   1 if [[ $part1 ]]; then
   2
   3 read input
   4 unset houses
   5 declare -A houses
   6 x=0 y=0
   7 houses[0/0]=1
   8 while test "$input"; do
   9     case ${input%%${input#?}} in
  10         '<') x=$((x-1)) ;;
  11         ^)   y=$((y+1)) ;;
  12         '>') x=$((x+1)) ;;
  13         v)   y=$((y-1)) ;;
  14         *) echo 'unexpected input'; exit 1 ;;
  15     esac
  16     houses[$x/$y]=$(( ${houses[$x/$y]} +1 ))
  17     input=${input#?}
  18 done
  19 echo ${houses[*]} | tr ' ' '\n' | wc -l
  20
  21 else # part 2
  22
  23 read input
  24 unset houses
  25 declare -A houses
  26 x1=0 y1=0
  27 x2=0 y2=0
  28 houses[0/0]=2
  29 while test "$input"; do
  30     case ${input%%${input#?}} in
  31         '<') x1=$((x1-1)) ;;
  32         ^)   y1=$((y1+1)) ;;
  33         '>') x1=$((x1+1)) ;;
  34         v)   y1=$((y1-1)) ;;
  35         *) echo 'unexpected input'; exit 1 ;;
  36     esac
  37     houses[$x1/$y1]=$(( ${houses[$x1/$y1]} +1 ))
  38     input=${input#?}
  39     case ${input%%${input#?}} in
  40         '<') x2=$((x2-1)) ;;
  41         ^)   y2=$((y2+1)) ;;
  42         '>') x2=$((x2+1)) ;;
  43         v)   y2=$((y2-1)) ;;
  44         *) echo 'unexpected input'; exit 1 ;;
  45     esac
  46     houses[$x2/$y2]=$(( ${houses[$x2/$y2]} +1 ))
  47     input=${input#?}
  48 done
  49 echo ${houses[*]} | tr ' ' '\n' | wc -l
  50
  51 fi