Day 15 broken part 1

2024-12-15 15:50:45 +08:00
parent 9492a8ae9a
commit 23076697cf
5 changed files with 202 additions and 0 deletions
--- a/2024/day-15/solution-1.sh
+++ b/2024/day-15/solution-1.sh
@ -0,0 +1,112 @@
+#!/usr/bin/env bash
+
+MAP_FILE=input-map
+DIRECTIONS_FILE=input-movements
+MAP_WIDTH=$(( $( head -1 "$MAP_FILE" | wc -c ) -1 ))
+#MAP_HEIGHT=$( < "$MAP_FILE" wc -l )
+
+# Load map
+read -r -a MAP_ARRAY <<< "$( < "$MAP_FILE" paste -s -d "" | sed -E 's/(.)(.)/\1 \2 /g' )"
+printf "%s " "${MAP_ARRAY[@]}" | fold -w $(( MAP_WIDTH * 2 ))
+printf "\n"
+MAP_LEN=${#MAP_ARRAY[@]}
+
+# Count boxes
+BOX_COUNT=0
+for (( i=0; i<MAP_LEN; i++ ))
+do
+  if [[ ${MAP_ARRAY[i]} == "O" ]]
+  then
+    (( BOX_COUNT++ ))
+  fi
+done
+printf "Box count: %s\n" "$BOX_COUNT"
+
+# Get robot position
+for (( i=0; i<MAP_LEN; i++ ))
+do
+  if [[ ${MAP_ARRAY[i]} == "@" ]]
+  then
+    ROBOT_POSITION=$i
+    break
+  fi
+done
+printf "Robot position : %s\n" "$ROBOT_POSITION"
+
+# Hardcode direction values
+UP=$(( - MAP_WIDTH ))
+DOWN=$MAP_WIDTH
+LEFT=-1
+RIGHT=1
+
+# Iterate through directions
+while read -r DIRECTION
+do
+
+  # Interpret directions
+  if [[ $DIRECTION == "^" ]]
+  then
+    DIRECTION_VALUE=$UP
+  elif [[ $DIRECTION == "v" ]]
+  then
+    DIRECTION_VALUE=$DOWN
+  elif [[ $DIRECTION == "<" ]]
+  then
+    DIRECTION_VALUE=$LEFT
+  elif [[ $DIRECTION == ">" ]]
+  then
+    DIRECTION_VALUE=$RIGHT
+  fi
+
+  NEXT_POSITION=$(( ROBOT_POSITION + DIRECTION_VALUE ))
+
+  if [[ ${MAP_ARRAY[$NEXT_POSITION]} == "O" ]] # Box in front
+  then
+    END_POSITION=$(( NEXT_POSITION + DIRECTION_VALUE ))
+    while [[ ${MAP_ARRAY[$END_POSITION]} == "O" ]]
+    do
+      (( END_POSITION+=DIRECTION_VALUE ))
+    done
+    if [[ ${MAP_ARRAY[$END_POSITION]} == '#' ]]
+    then
+      : # Boxes are stacked up against wall
+    elif [[ ${MAP_ARRAY[$END_POSITION]} == "." ]]
+    then
+      # Move the box
+      MAP_ARRAY[END_POSITION]=O
+      MAP_ARRAY[NEXT_POSITION]=.
+      # Move the robot
+      MAP_ARRAY[ROBOT_POSITION]=.
+      ROBOT_POSITION=$NEXT_POSITION
+      MAP_ARRAY[ROBOT_POSITION]=@
+    fi
+  elif [[ ${MAP_ARRAY[$NEXT_POSITION]} == "#" ]] # Wall in front, do nothing
+  then
+    continue
+  elif [[ ${MAP_ARRAY[$NEXT_POSITION]} == "." ]] # Empty space, move forward
+  then
+    # Move the robot
+    MAP_ARRAY[ROBOT_POSITION]=.
+    ROBOT_POSITION=$NEXT_POSITION
+    MAP_ARRAY[ROBOT_POSITION]=@
+  fi
+
+done <<< "$( < "$DIRECTIONS_FILE" sed -E 's/(.)(.)/\1 \2 /g' | tr ' ' '\n' )"
+
+printf "%s " "${MAP_ARRAY[@]}" | fold -w $(( MAP_WIDTH * 2 ))
+printf "\n"
+
+# Calculate GPS values for boxes
+SUM=0
+BOX_COUNT=0
+for (( i=0; i<MAP_LEN; i++ ))
+do
+  if [[ ${MAP_ARRAY[i]} == "O" ]]
+  then
+    (( BOX_COUNT++ ))
+    (( SUM+=( (i / MAP_WIDTH) * 100 ) )) # Add Y axis
+    (( SUM+=( i % MAP_WIDTH ) )) # Add x axis
+  fi
+done
+printf "Sum: %s\n" "$SUM"
+printf "Box count: %s\n" "$BOX_COUNT"