Day 13

13/01.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+declare -A dots
+folds=()
+
+while read line; do
+  if [[ $line == *','* ]]; then
+    dots[$line]=1
+  else
+    folds+=( $(sed 's/fold along //' <<< $line) )
+  fi
+done
+
+fold=${folds[0]}
+fold_axis=$(sed 's/=.*$//' <<< $fold)
+fold_coord=$(sed 's/^.*=//' <<< $fold)
+new_dots=()
+todel_dots=()
+
+for dot in ${!dots[@]}; do
+  dot_x=$(sed 's/,.*$//' <<< $dot)
+  dot_y=$(sed 's/^.*,//' <<< $dot)
+  if [[ $fold_axis == 'x' ]]; then
+    if [ $dot_x -gt $fold_coord ]; then
+      new_dots+=( "$((fold_coord*2-dot_x)),$dot_y" )
+      todel_dots+=( $dot )
+    fi
+  else
+    if [ $dot_y -gt $fold_coord ]; then
+      new_dots+=( "$dot_x,$((fold_coord*2-dot_y))" )
+      todel_dots+=( $dot )
+    fi
+  fi
+done
+
+for todel_dot in ${todel_dots[@]}; do
+  unset dots[$todel_dot]
+done
+
+for new_dot in ${new_dots[@]}; do
+  dots[$new_dot]=1
+done
+
+echo ${#dots[@]}

13/02.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+declare -A dots
+folds=()
+min_x=-1
+min_y=-1
+
+while read line; do
+  if [[ $line == *','* ]]; then
+    dots[$line]=1
+  else
+    folds+=( $(sed 's/fold along //' <<< $line) )
+  fi
+done
+
+for fold in ${folds[@]}; do
+  fold_axis=$(sed 's/=.*$//' <<< $fold)
+  fold_coord=$(sed 's/^.*=//' <<< $fold)
+  new_dots=()
+  todel_dots=()
+  
+  if [[ $fold_axis == 'x' ]] && { [ $fold_coord -lt $min_x ] || [ $min_x -eq -1 ] ;}; then
+    min_x=$fold_coord
+  elif [[ $fold_axis == 'y' ]] && { [ $fold_coord -lt $min_y ] || [ $min_y -eq -1 ] ;}; then
+    min_y=$fold_coord
+  fi
+
+  for dot in ${!dots[@]}; do
+    dot_x=$(sed 's/,.*$//' <<< $dot)
+    dot_y=$(sed 's/^.*,//' <<< $dot)
+    if [[ $fold_axis == 'x' ]]; then
+      if [ $dot_x -gt $fold_coord ]; then
+        new_dots+=( "$((fold_coord*2-dot_x)),$dot_y" )
+        todel_dots+=( $dot )
+      fi
+    else
+      if [ $dot_y -gt $fold_coord ]; then
+        new_dots+=( "$dot_x,$((fold_coord*2-dot_y))" )
+        todel_dots+=( $dot )
+      fi
+    fi
+  done
+
+  for todel_dot in ${todel_dots[@]}; do
+    unset dots[$todel_dot]
+  done
+
+  for new_dot in ${new_dots[@]}; do
+    dots[$new_dot]=1
+  done
+done
+
+for j in $(seq 0 $min_y); do
+  for i in $(seq 0 $min_x); do
+    if [ ${dots["$i,$j"]} ]; then
+      echo -n '#'
+    else
+      echo -n ' '
+    fi
+  done
+  echo
+done