advent-of-code/2024/day-12/solution-2.sh

#!/usr/bin/env bash

FUNCNEST=99999
FILE=test-input-1
read -r -a MAP_ARRAY <<< "$( < "$FILE" paste -s -d "" | sed -E 's/(.)/\1\ /g' )"
MAP_LEN=${#MAP_ARRAY[@]}
MAP_WIDTH=$(( $( head -1 "$FILE" | wc -c ) -1 ))
MAP_WIDTH_INV=$(( 0 - MAP_WIDTH ))
MAP_HEIGHT=$( < "$FILE" wc -l )
printf "Len: %s Width: %s Height: %s\n" "$MAP_LEN" "$MAP_WIDTH" "$MAP_HEIGHT"

# Check if tiles are adjacent and do not violate bounds
check_adjacent () {
  # Check for out of map bounds
  if [[ $2 -lt 0 ]] || [[ $2 -gt $MAP_LEN ]] ; then return 1 ; fi

  DIFF=$(( $2 - $1 ))
  # Valid adjacent distances
  if [[ $DIFF -eq 1 ]] || [[ $DIFF -eq -1 ]] || [[ $DIFF -eq $MAP_WIDTH ]] || [[ $DIFF -eq $MAP_WIDTH_INV ]] ; then : ; else return 1 ; fi

  # Check for left/right bounds
  if [[ $DIFF -eq 1 ]] && [[ $(( $2 % MAP_WIDTH )) -eq 0 ]] ; then return 1 ; fi
  if [[ $DIFF -eq -1 ]] && [[ $(( $1 % MAP_WIDTH )) -eq 0 ]] ; then return 1 ; fi
}

# Basically recurse over kv and "consume" all adjacent tiles
# All tiles that are consumed are adjacent
check_and_unset () {

  local KV_I=${1%% *} # Remove trailing whitespace
  (( AREA++ ))
  VALUE=${KV_CACHE[$KV_I]}
  unset "KV_CACHE[$KV_I]" # "Take" it

  printf "max: %s peri: %s area: %s key: %s val: %s\n" "$MAX_PERI" "$PERI_NUM" "$AREA" "$1" "$VALUE" >&2

  # As a square, expect width and height to always be preserved
  # Recursion should always be in sequence

  unset IFS; read -r -a VAL_ARRAY <<< "$VALUE"
  # Loop through adjacent tiles and recurse
  for VAL in "${VAL_ARRAY[@]}" # VAL_ARRAY is always sorted
  do
    VAL_IDX=${VAL%% *}
    if [[ -v KV_CACHE[$VAL_IDX] ]] # Check if tile has been "taken"
    then 
      check_and_unset "$VAL_IDX"
    fi
  done
}

while read -r CHAR
do
  # Get all indexes for a plant
  read -r -a CHAR_ARRAY <<< "$(
    for (( i=0; i<MAP_LEN; i++ ))
    do
      if [[ ${MAP_ARRAY[$i]} == "$CHAR" ]]
      then
        printf "%s " "$i"
      fi
    done
  )"

  #{ 
  #  printf "For char %s \n" "$CHAR"
  #  printf "%s " "${CHAR_ARRAY[@]}"
  #  printf "\n" 
  #} >&2

  declare -A KV_CACHE
  IFS=':'; while read -r VAR1 VAR2
  do
    #printf "VAR1: %s VAR2: %s\n" "$VAR1" "$VAR2" >&2
    KV_CACHE[$VAR1]=$VAR2
  done <<< "$(
    # Find all adjacent tiles
    for (( i=0; i<${#CHAR_ARRAY[@]}; i++ ))
    do
      NUM_ADJ=0
      printf "%s:" "${CHAR_ARRAY[i]}"
      MIN=$(( $(( i-MAP_WIDTH )) < 0        ? 0                  : $(( i-MAP_WIDTH )) ))
      MAX=$(( $(( i+MAP_WIDTH )) < MAP_LEN  ? $(( i+MAP_WIDTH )) : $(( MAP_LEN     )) ))
      for (( j=MIN; j<MAX; j++ )) # There can only be MAP_WIDTH number of elements within valid range
      do
        if check_adjacent "${CHAR_ARRAY[i]}" "${CHAR_ARRAY[j]}"
        then
          printf "%s " "${CHAR_ARRAY[j]}"
          (( NUM_ADJ++ ))
        fi
      done
      printf "\n"
      #printf "Num adj for %s idx %s is %s\n" "$CHAR" "${CHAR_ARRAY[$i]}" "$NUM_ADJ" >&2
    done
  )"

  # Iterate through
  for CH in "${CHAR_ARRAY[@]}"
  do
    CHAR=${CH%% *} # Remove trailing whitespace
    if ! [[ -v KV_CACHE[$CHAR] ]]; then continue; fi
    PERI_NUM=4 # Number of perimeters of a square
    AREA=0
    ROW=0
    check_and_unset "$CHAR"
    printf "char: %s max: %s peri: %s area: %s\n" "$CHAR" "$MAX_PERI" "$PERI_NUM" "$AREA" >&2
    printf "%s\n" "$(( PERI_NUM * AREA ))"
  done
# Get all plants
#done <<< "$( < "$FILE" grep -o '[A-Z]' | sort -u | grep -o '[A-Z]*' )"
done <<< "$( < "$FILE" grep -o '[A-Z]' | sort -u | grep -o '[A-Z]*' )" |
  paste -s -d "+" | bc