advent-of-code/2024/day-17/solution-1.sh

#!/usr/bin/env bash

FILE=$1
ITER=99
DEBUG=false

REG_A=$(grep 'Register A:' "$FILE" | cut -f2 -d: )
REG_B=$(grep 'Register B:' "$FILE" | cut -f2 -d: )
REG_C=$(grep 'Register C:' "$FILE" | cut -f2 -d: )
read -r -a INPUT <<< "$(grep 'Program:' "$FILE" | cut -f2 -d: | tr ',' ' ' )"
INPUT_LEN=${#INPUT[@]}

printf "Registers A: %s B: %s C: %s\n" "$REG_A" "$REG_B" "$REG_C" >&2
printf "Input : " >&2
printf "%s " "${INPUT[@]}" >&2
printf "\n" >&2

# Load machine operations
. machine.sh

POINTER=0
while [[ $POINTER -lt $INPUT_LEN ]]
do
  OPCODE=${INPUT[$POINTER]}
  OPERAND=${INPUT[$POINTER+1]}
  if [[ $OPCODE -eq 0 ]]
  then
    adv "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 1 ]]
  then
    bxl "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 2 ]]
  then
    bst "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 3 ]]
  then
    # jnz itself moves the pointer
    jnz "$OPERAND"
  elif [[ $OPCODE -eq 4 ]]
  then
    bxc "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 5 ]]
  then
    out "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 6 ]]
  then
    bdv "$OPERAND"
    (( POINTER+=2 ))
  elif [[ $OPCODE -eq 7 ]]
  then
    cdv "$OPERAND"
    (( POINTER+=2 ))
  fi
  printf "Registers A : %s B: %s C : %s\n" "$REG_A" "$REG_B" "$REG_C" >&2
  printf "Pointer : %s\n" "$POINTER" >&2
  (( ITER-- ))
  if [[ $ITER -eq 0 ]] ; then break ;fi
done | paste -s -d ","