day10/common.sh

   1 declare -A asteroids
   2 declare __asteroids_grid_height
   3 declare __asteroids_grid_width
   4
   5 get_grid_height() {
   6     echo $__asteroids_grid_height
   7 }
   8
   9 get_grid_width() {
  10     echo $__asteroids_grid_width
  11 }
  12
  13 read_file() {
  14     filename="$1"
  15
  16     if [ ! -e "$filename" ]; then
  17         echo "Couldn't find file: $filename"
  18         exit 2
  19     fi
  20
  21     exec 3<"$filename"
  22     unset asteroids
  23     declare -g -A asteroids
  24
  25     __asteroids_grid_height=0
  26     __asteroids_grid_width=0
  27
  28     while read -u 3 line; do
  29         __asteroids_grid_width=${#line}
  30         for (( a=0; a<${#line}; a++ )); do
  31             char=${line:$a:1}
  32             if [ "${char}" == "#" ]; then
  33                 asteroids[$a,$__asteroids_grid_height]=0
  34             fi
  35         done
  36         __asteroids_grid_height=$((__asteroids_grid_height+1))
  37     done
  38 }
  39
  40 get_vector() {
  41     local x1=$1
  42     local y1=$2
  43     local x2=$3
  44     local y2=$4
  45
  46     x_diff=$(($x2 - $x1))
  47     y_diff=$(($y2 - $y1))
  48
  49     echo "$x_diff,$y_diff"
  50 }
  51
  52 get_asteroids_vector() {
  53     local a1=$1
  54     local a2=$2
  55
  56     local x1=${a1%,*}
  57     local y1=${a1#*,}
  58     local x2=${a2%,*}
  59     local y2=${a2%*,}
  60
  61     get_vector $x1 $y1 $x2 $y2
  62 }
  63
  64 get_angle() {
  65     local a1=$1
  66     local a2=$2
  67
  68     local vector=$(get_asteroids_vector $a1 $a2)
  69     local move_x=${vector%,*}
  70     local move_y=${vector#*,}
  71
  72     val="$(calc -p 'round(((90 + ((180/pi()) * atan2('$move_y','$move_x'))) % 360) * 100000000) / 100000000')"
  73     echo "$val"
  74 }
  75
  76 get_closest_asteroid() {
  77     local asteroids=$1
  78
  79     local IFS="|"
  80     local min_dist=-1
  81     local nearest_asteroid=
  82     local x=0
  83     local y=0
  84
  85     for asteroid in $asteroids; do
  86         vector=$(get_asteroids_vector $our_asteroid $asteroid)
  87         x=${vector%,*}
  88         y=${vector#*,}
  89         # use absolute numbers for length calculation!
  90         x=${x#-}
  91         y=${y#-}
  92
  93         distance=$((x+y))
  94         if [ $distance -lt $min_dist -o $min_dist -eq -1 ]; then
  95             min_dist=$distance
  96             nearest_asteroid=$asteroid
  97         fi
  98     done
  99
 100     echo $nearest_asteroid
 101 }
 102
 103 remove_asteroid_from_string() {
 104     local asteroids=$1
 105     local asteroid=$2
 106     local new_asteroids=
 107     local a
 108
 109     local IFS="|"
 110     local seperator=""
 111
 112     for a in $asteroids; do
 113         if [ "$a" != "$asteroid" ]; then
 114             new_asteroids+="${seperator}$a"
 115         fi
 116         if [ "x$new_asteroids" != "x" ]; then
 117             seperator="|"
 118         fi
 119     done
 120
 121     echo "$new_asteroids"
 122 }
 123
 124 get_angles_list() {
 125     local -n __asteroid_angles=$1
 126     printf "%s\n" "${!__asteroid_angles[@]}" | sort -g
 127 }
 128