day10/check_asteroids.sh

   1 #!/bin/bash
   2
   3 set -u
   4 set -e
   5
   6 basedir=$(dirname $(readlink -f ${BASH_SOURCE}))
   7
   8 . $basedir/common.sh
   9
  10 filename=${1:-$basedir/3_4_8.txt}
  11
  12 read_file $filename
  13
  14 declare -A cansee
  15 declare -A cantsee
  16
  17 debug_line=true # default to not actually outputting any debug info
  18
  19 if [ ${DEBUG:-0} -gt 0 ]; then
  20     debug_line=debug_line
  21 fi
  22
  23 debug_line() {
  24     line="$@"
  25     echo "$line" >&2
  26 }
  27
  28 # lets be silly and use the stuff from zap to build the lists instead
  29 best_count=0
  30 best_ast=
  31 cur_ast_num=0
  32 total_asts=${#asteroids[@]}
  33 for asteroid in ${!asteroids[@]}; do
  34     percent=$((100*$cur_ast_num / $total_asts))
  35     printf '\r%02d%% complete' $percent
  36
  37     # get a full list of angles for each other asteroid
  38     declare -A asteroid_angles
  39     for asteroid2 in ${!asteroids[@]}; do
  40         if [ $asteroid == $asteroid2 ]; then
  41             continue
  42         fi
  43
  44         angle=$(get_angle $asteroid $asteroid2)
  45         asteroid_angles[$angle]=1
  46     done
  47     count=${#asteroid_angles[@]}
  48     if [ $count -gt $best_count ]; then
  49         best_count=$count
  50         best_ast=$asteroid
  51     fi
  52     asteroid[$asteroid]=${#asteroid_angles[@]}
  53     unset asteroid_angles
  54     cur_ast_num=$((cur_ast_num+1))
  55 done
  56 printf '\r                              \r'
  57
  58 echo "Found $best_ast with $best_count asteroids"
  59 exit 0