advent-of-code-2021/18/02.sh

#!/bin/bash

representations=()
max_magnitude=0
while read line; do
  representation=()
  nests=0
  for ((i=0;i<${#line};i++)); do
    case ${line:$i:1} in
      '[')
        nests=$((nests+1))
        ;;
      ']')
        nests=$((nests-1))
        ;;
      ',')
        ;;
      *)
        representation+=( $nests':'${line:$i:1} )
        ;;
    esac
  done
  representations+=( $(sed 's/ /_/g' <<< ${representation[@]}) )
done

for ((k=0;k<${#representations[@]};k++)); do
  for ((j=0;j<${#representations[@]};j++)); do
    if [ $j -eq $k ]; then
      continue
    fi
    representation=( $(sed 's/_/ /g' <<< ${representations[$k]}) )
    sum_representation=( $(sed 's/_/ /g' <<< ${representations[$j]}) )
    for ((i=0;i<${#representation[@]};i++)); do
      node=${representation[$i]}
      node_nests=${node%':'*}
      node_value=${node#*':'}
      representation[$i]=$((node_nests+1))':'$node_value
    done
    for ((i=0;i<${#sum_representation[@]};i++)); do
      node=${sum_representation[$i]}
      node_nests=${node%':'*}
      node_value=${node#*':'}
      representation+=( $((node_nests+1))':'$node_value )
    done
    changes=1
    while [ $changes -eq 1 ]; do
      changes=0
      for ((i=0;i<${#representation[@]};i++)); do
        node=${representation[$i]}
        node_nests=${node%':'*}
        node_value=${node#*':'}
        if [ $node_nests -gt 4 ]; then 
          following_node=${representation[$((i+1))]}
          following_node_nests=${following_node%':'*}
          following_node_value=${following_node#*':'}
          if [ $node_nests -eq $following_node_nests ]; then
            changes=1
            new_representation=()
            if [ $i -gt 0 ]; then
              prev_value=${representation[$((i-1))]}
              prev_nests=${prev_value%':'*}
              prev_value=${prev_value#*':'}
              representation[$((i-1))]=$prev_nests':'$((prev_value+node_value))
              new_representation+=( ${representation[@]:0:$i} )
            fi
            new_representation+=( $((node_nests-1))':'0 )
            if [ $i -lt $((${#representation[@]}-2)) ]; then
              next_value=${representation[$((i+2))]}
              next_nests=${next_value%':'*}
              next_value=${next_value#*':'}
              representation[$((i+2))]=$next_nests':'$((next_value+following_node_value))
              new_representation+=( ${representation[@]:$((i+2))} )
            fi
            representation=( ${new_representation[@]} )
            break
          fi
        fi
      done
      if [ $changes -eq 0 ]; then
        for ((i=0;i<${#representation[@]};i++)); do
          node=${representation[$i]}
          node_nests=${node%':'*}
          node_value=${node#*':'}
          if [ $node_value -gt 9 ]; then
            changes=1
            new_representation=()
            if [ $i -gt 0 ]; then
              new_representation+=( ${representation[@]:0:$i} )
            fi
            value_left=$(($node_value/2))
            value_right=$value_left
            if [ $((node_value%2)) -eq 1 ]; then
              value_right=$((value_right+1))
            fi
            new_representation+=( $((node_nests+1))':'$value_left $((node_nests+1))':'$value_right )
            if [ $i -lt $((${#representation[@]}-1)) ]; then
              new_representation+=( ${representation[@]:$((i+1))} )
            fi
            representation=( ${new_representation[@]} )
            break
          fi
        done
      fi
    done

    declare -A tree_representation
    
    last_key=''
    for node in ${representation[@]}; do
      node_nests=${node%':'*}
      node_value=${node#*':'}
      current_key=''
      if [ -z $last_key ]; then
        current_key=$(for ((i=0;i<$node_nests;i++)); do echo -n 0; done)
        tree_representation[$current_key]=$node_value
      else
        if [ ${#last_key} -eq $node_nests ]; then
          current_key=$(( 2#$last_key + 2#01 ))
          current_key=$(echo "ibase=A;obase=2;$current_key" | bc)
          while [ ${#current_key} -lt $node_nests ]; do
            current_key=0$current_key
          done
          tree_representation[$current_key]=$node_value
        elif [ ${#last_key} -lt $node_nests ]; then
          current_key=$(( 2#$last_key + 2#01 ))
          current_key=$(echo "ibase=A;obase=2;$current_key" | bc)
          while [ ${#current_key} -lt ${#last_key} ]; do
            current_key=0$current_key
          done
          while [ ${#current_key} -lt $node_nests ]; do
            current_key=${current_key}0
          done
          tree_representation[$current_key]=$node_value
        else
          current_key=${last_key:0:$node_nests}
          current_key=$(( 2#$current_key + 2#01 ))
          current_key=$(echo "ibase=A;obase=2;$current_key" | bc)
          while [ ${#current_key} -lt $node_nests ]; do
            current_key=0$current_key
          done
          tree_representation[$current_key]=$node_value
        fi
      fi
      last_key=$current_key
    done
    
    magnitude=0
    for tree_representation_node in ${!tree_representation[@]}; do
      temp_magnitude=${tree_representation[$tree_representation_node]}
      for ((i=0;i<${#tree_representation_node};i++)); do
        if [ ${tree_representation_node:$i:1} -eq 0 ]; then
          temp_magnitude=$((temp_magnitude*3))
        else
          temp_magnitude=$((temp_magnitude*2))
        fi
      done
      magnitude=$((magnitude+temp_magnitude))
    done
    if [ $magnitude -gt $max_magnitude ]; then
      max_magnitude=$magnitude
    fi
    unset tree_representation
  done
done


echo $max_magnitude