day02/computer.sh

   1 #!/bin/bash
   2
   3 filename=${1:-input.txt}
   4
   5 exec 3<"$filename"
   6
   7 OLDIFS=$IFS
   8 IFS="," read -u 3 -a orig_data
   9 IFS=$OLDIFS
  10
  11 run_program() {
  12     noun=$1
  13     verb=$2
  14     data=("${orig_data[@]}")
  15     data[1]=$noun
  16     data[2]=$verb
  17     pos=0
  18     while [ $pos -le ${#data[@]} ]; do
  19         loc1=${data[$((pos+1))]}
  20         loc2=${data[$((pos+2))]}
  21         res_loc=${data[$((pos+3))]}
  22         case ${data[$pos]} in
  23             1)
  24                 data[$res_loc]=$((${data[$loc1]}+${data[$loc2]}))
  25                 ;;
  26             2)
  27                 data[$res_loc]=$((${data[$loc1]}*${data[$loc2]}))
  28                 ;;
  29             99)
  30                 break
  31                 ;;
  32             *)
  33                 echo "Invalid opcode: ${data[$pos]} at position $pos"
  34                 exit 1
  35         esac
  36         pos=$((pos+4))
  37     done
  38
  39     echo "${data[0]}"
  40 }
  41
  42 echo "Part 1: $(run_program 12 2)"
  43
  44 desired_output=19690720
  45
  46 for (( noun=0; noun < 100; noun++)); do
  47     for (( verb=0; verb < 100; verb++)); do
  48         if [ $(run_program $noun $verb) -eq $desired_output ]; then
  49             echo "Part 2: $((noun * 100 + $verb)) $noun, $verb"
  50             exit 0
  51         fi
  52     done
  53 done