day04/bingo.sh

   1 #!/bin/bash
   2
   3 set -e
   4 set -u
   5
   6 filename=${1:-example.txt}
   7
   8 bold=$(tput bold)
   9 normal=$(tput sgr0)
  10
  11 # each board is a 5*5 grid, so that's handy, we'll store all the boards in one
  12 # array, then create a second array that shows which matches we have, we can
  13 # select any given board by limiting to a range of 25 values from the array
  14
  15 exec 3<"$filename"
  16
  17 # first line is the draws, so read that in to an array too
  18 OLDIFS="$IFS"
  19 IFS=","
  20 read -u 3 -a draw
  21
  22 read -u 3 line
  23
  24 IFS="   "
  25 line_count=0
  26
  27 declare -a boards
  28 declare -a checked
  29
  30 while read -u 3 -a row; do
  31     ((line_count+=1))
  32     boards+=("${row[@]}")
  33     if [ $line_count -eq 5 ]; then
  34         read -u 3 line || true
  35         line_count=0
  36     fi
  37 done
  38
  39 for x in ${boards[@]}; do
  40     checked+=(0)
  41 done
  42
  43 display_board() {
  44     local board_number=$1
  45     offset=$((25*$board_number))
  46
  47     count=0
  48
  49     for val in "${boards[@]:$offset:25}"; do
  50         if [ ${checked[$((offset+$count))]} -eq 1 ]; then
  51             echo -n "${bold}"
  52         fi
  53         ((count+=1))
  54         printf "%2d " $val
  55         echo -n "${normal}"
  56         if [ $((count%5)) -eq 0 ]; then
  57             echo
  58         fi
  59     done
  60     echo
  61 }
  62
  63 check_board() {
  64     local board_number=$1
  65     local drawn_number=$2
  66     offset=$((25*$board_number))
  67
  68     count=0
  69     for val in "${boards[@]:$offset:25}"; do
  70         if [ $val -eq $drawn_number ]; then
  71             checked[$((offset+$count))]=1
  72         fi
  73         ((count+=1))
  74     done
  75
  76     row=0
  77     col=0
  78     declare -a row_matches=(0 0 0 0 0)
  79     declare -a col_matches=(0 0 0 0 0)
  80
  81     for val in "${checked[@]:$offset:25}"; do
  82         if [ $val -eq 1 ]; then
  83             ((col_matches[$col]+=1))
  84             ((row_matches[$row]+=1))
  85         fi
  86         ((col+=1))
  87         if [ $col -eq 5 ]; then
  88             col=0
  89             ((row+=1))
  90         fi
  91     done
  92
  93     for row in "${row_matches[@]}"; do
  94         if [ $row -eq 5 ]; then
  95             return 0
  96         fi
  97     done
  98
  99     for col in "${col_matches[@]}"; do
 100         if [ $col -eq 5 ]; then
 101             return 0
 102         fi
 103     done
 104
 105     return 1
 106 }
 107
 108 get_unmarked_count() {
 109     local board_number=$1
 110     local offset=$((board_number*25))
 111     local count=0
 112
 113     for ((i=0; i<25; i++)); do
 114         if [ ${checked[$(($offset+$i))]} -eq 0 ]; then
 115             ((count+=${boards[$(($offset+$i))]}))
 116         fi
 117     done
 118
 119     echo $count
 120 }
 121
 122 declare -a completed_boards=()
 123
 124 in_array() {
 125     local value=$1
 126     local -n array=$2
 127
 128     for val in "${array[@]}"; do
 129         if [ $val -eq $value ]; then
 130             return 0
 131         fi
 132     done
 133
 134     return 1
 135 }
 136
 137 first_board=-1
 138 first_board_last_number=-1
 139 last_board_last_number=-1
 140
 141 for number in "${draw[@]}"; do
 142     for (( board=0; board<$((${#boards[@]} / 25)); board++ )); do
 143         if ( ! in_array $board completed_boards ); then
 144             check_board $board $number && { if [ $first_board -eq -1 ]; then first_board=$board; first_board_last_number=$number; fi; completed_boards+=( $board ); } || true
 145             if [ ${#completed_boards[@]} -eq $((${#boards[@]} / 25)) ]; then
 146                 last_board_last_number=$number
 147                 break 2
 148             fi
 149         fi
 150     done
 151 done
 152
 153 echo "Board matched: $first_board"
 154 echo "Last number drawn: $first_board_last_number"
 155 echo
 156 display_board $first_board
 157
 158 unmarked=$(get_unmarked_count $first_board)
 159
 160 echo "$unmarked * $first_board_last_number = "$((unmarked*$first_board_last_number))
 161
 162 echo "Last board matched: "${completed_boards[-1]}
 163 echo "Last number drawn: $last_board_last_number"
 164 echo
 165 display_board ${completed_boards[-1]}
 166
 167 unmarked=$(get_unmarked_count ${completed_boards[-1]})
 168
 169 echo "$unmarked * $last_board_last_number = "$((unmarked*$last_board_last_number))