working builds

2024/day-8/solution-2.sh

@@ -28,9 +28,11 @@ do
   for (( i=0; i<${#IDX_ARRAY[@]}-1; i++ ))
   do
     A=${IDX_ARRAY[i]}
+    SHADOW_ARRAY[A]=X
     for (( j=i+1; j<${#IDX_ARRAY[@]}; j++ ))
     do
       B=${IDX_ARRAY[j]}
+      SHADOW_ARRAY[B]=X
       DIFF=$(( B - A ))
       VDIFF=$(( (B / LEN) - (A / LEN) ))
       # Assign heads
@@ -38,11 +40,11 @@ do
       while true
       do
         HEAD=$(( A - DIFF * HEADC ))
-	HEADVDIFF=$(( ( (A / LEN) - (HEAD / LEN) ) / HEADC ))
+	HEADVDIFF=$(( (A / LEN) - (HEAD / LEN) ))
         # Check if out of bounds
         if [[ $HEAD -lt ${#MAP_ARRAY[@]} ]] && \
            [[ $HEAD -ge 0 ]] && \
-           [[ $HEADVDIFF -eq $VDIFF ]]
+	   [[ $HEADVDIFF -eq $(( VDIFF * HEADC )) ]]
         then
           SHADOW_ARRAY[HEAD]=X # Mark on shadow map
 	  (( HEADC++ ))
@@ -55,11 +57,11 @@ do
       while true
       do
         TAIL=$(( B + DIFF * TAILC ))
-	TAILVDIFF=$(( ( (TAIL / LEN) - (B / LEN) ) / TAILC ))
+	TAILVDIFF=$(( (TAIL / LEN) - (B / LEN) ))
         # Check if out of bounds
         if [[ $TAIL -lt ${#MAP_ARRAY[@]} ]] && \
            [[ $TAIL -ge 0 ]] && \
-           [[ $TAILVDIFF -eq $VDIFF ]]
+	   [[ $TAILVDIFF -eq $(( VDIFF * TAILC )) ]]
         then
           SHADOW_ARRAY[TAIL]=X # Mark on shadow map
 	  (( TAILC++ ))