2018/day2a.sh

   1 two=0
   2 three=0
   3 while read line; do
   4     unset a
   5     declare -A a
   6     while [[ $line =~ (.)(.*) ]]; do
   7         letter=${BASH_REMATCH[1]}
   8         : $((a[$letter]++))
   9         line=${BASH_REMATCH[2]}
  10     done
  11     have2=0 have3=0
  12     for letter in {a..z}; do
  13         if test "${a[$letter]}" = 2; then
  14             have2=1
  15         elif test "${a[$letter]}" = 3; then
  16             have3=1
  17         fi
  18     done
  19     : $(( two += have2 )) $(( three += have3 ))
  20 done
  21 echo checksum: $(( two * three ))