Solution 1 day 5

2024/day-6/solution-1.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+
+ARRAY_SHAPE=10 # It's a square
+FILENAME=test-input
+read -r -a MAP_ARRAY <<< "$( paste -s -d '' "$FILENAME" | sed -E 's/(.)/\1\ /g' )"
+
+# Get initial position
+POSITION=$(( ( $( grep -n '\^' "$FILENAME" | cut -f1 -d: ) -1 ) * ARRAY_SHAPE -1 + $( grep -o '.*\^' "$FILENAME" | wc -c ) -1 ))
+MAP_ARRAY[POSITION]=X # Remove position after save
+
+# up = 0, right = 1, down = 2, left = 3, following 90 degree turn
+TURNS=0
+while true
+do
+  EXIT=1
+
+  # Get direction and travel 
+  DIRECTION=$(( TURNS % 4 ))
+  if [[ $DIRECTION -eq 0 ]] # up
+  then
+    TRAVEL=-$ARRAY_SHAPE
+    LIMIT=$(( POSITION % ARRAY_SHAPE ))
+  elif [[ $DIRECTION -eq 1 ]] # right
+  then
+    TRAVEL=1
+    LIMIT=$(( (POSITION / ARRAY_SHAPE + 1) * ARRAY_SHAPE )) # Never verified
+  elif [[ $DIRECTION -eq 2 ]] # down
+  then
+    TRAVEL=$ARRAY_SHAPE
+    LIMIT=$(( (POSITION % ARRAY_SHAPE) + (ARRAY_SHAPE * ARRAY_SHAPE) ))
+  elif [[ $DIRECTION -eq 3 ]] # left
+  then
+    TRAVEL=-1
+    LIMIT=$(( (POSITION / ARRAY_SHAPE) * ARRAY_SHAPE )) # Never verified
+  fi
+
+  while [[ ${MAP_ARRAY[$POSITION+$TRAVEL]} != '#' ]]
+  do
+    if [[ $POSITION -eq $LIMIT ]] # Walked out
+    then
+      EXIT=0
+      break
+    fi
+
+    MAP_ARRAY[POSITION]=X # Mark walking path
+    (( POSITION+=TRAVEL ))
+  done
+  
+  if [[ $EXIT -eq 0 ]] ; then break ; fi # Walked out
+
+  (( TURNS++ ))
+done
+
+# Count all coordinates
+printf "%s" "${MAP_ARRAY[@]}" | tee travel-path | sed 's/[^X]//g' | wc -c
+< travel-path fold -w $ARRAY_SHAPE