Day 18

18/01.sh

@@ -0,0 +1,156 @@
+#!/bin/bash
+
+representations=()
+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
+
+representation=( $(sed 's/_/ /g' <<< ${representations[0]}) )
+for ((j=1;j<${#representations[@]};j++)); do
+  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
+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
+
+echo $magnitude