commit 8490469fa2cd35ad0f82ae158e785fa5a0cdc4ad
parent 6e1c74890e2ea7d8033c1e9494f1186ea8101022
Author: Decay <decay@todayiwilllaunchmyinfantsonintoorbit.com>
Date: Thu, 8 Dec 2022 08:57:35 -0800
Day 8 (QuickBASIC)
Diffstat:
| A | 8/8.bas | | | 137 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 137 insertions(+), 0 deletions(-)
diff --git a/8/8.bas b/8/8.bas
@@ -0,0 +1,137 @@
+REM QBasic/QuickBasic implementation of AOC2022 day 8
+
+REM visibility reference constants; tree height is stored in forest%(x,y,HEIGHT)
+const TOPV = 0
+const LEFTV = 1
+const BOTTOMV = 2
+const RIGHTV = 3
+const HEIGHT = 4
+
+REM Open and read file
+open "input" for input as #1
+line input #1, line$
+let side% = len(line$)
+
+REM Create array to store the forest and visibilities, assume square
+dim forest%(side%, side%, 5)
+let visible% = 0
+
+REM Construct a matrix of the forest from file input and the top and left visibilities
+for y% = 1 to side%
+ if y% > 1 then
+ line input #1, line$
+ end if
+ for x% = 1 to side%
+ let tree$ = mid$(line$, x%, 1)
+ let forest%(x% - 1, y% - 1, HEIGHT) = asc(tree$) - 48
+
+ REM Determine visibility from the left
+ if x% = 1 then
+ forest%(0, y% - 1, LEFTV) = -1
+ elseif forest%(x% - 2, y% - 1, HEIGHT) > forest%(x% - 2, y% - 1, LEFTV) then
+ forest%(x% - 1, y% - 1, LEFTV) = forest%(x% - 2, y% - 1, HEIGHT)
+ else
+ forest%(x% - 1, y% - 1, LEFTV) = forest%(x% - 2, y% - 1, LEFTV)
+ end if
+
+ REM Determine visibility from the top
+ if y% = 1 then
+ forest%(x% - 1, 0, TOPV) = -1
+ elseif forest%(x% - 1, y% - 2, HEIGHT) > forest%(x% - 1, y% - 2, TOPV) then
+ forest%(x% - 1, y% - 1, TOPV) = forest%(x% - 1, y% - 2, HEIGHT)
+ else
+ forest%(x% - 1, y% - 1, TOPV) = forest%(x% - 1, y% - 2, TOPV)
+ end if
+ next x%
+next y%
+
+REM Close file
+close #1
+
+REM Go backward through the array and collect visibility in the opposite direction
+REM and count visible trees
+for y% = side% to 1 step - 1
+ for x% = side% to 1 step -1
+ REM Determine visibility from the right
+ if x% = side% then
+ forest%(side% - 1, y% - 1, RIGHTV) = -1
+ elseif forest%(x%, y% - 1, HEIGHT) > forest%(x%, y% - 1, RIGHTV) then
+ forest%(x% - 1, y% - 1, RIGHTV) = forest%(x%, y% - 1, HEIGHT)
+ else
+ forest%(x% - 1, y% - 1, RIGHTV) = forest%(x%, y% - 1, RIGHTV)
+ end if
+
+ REM Determine visibility from the bottom
+ if y% = side% then
+ forest%(x% - 1, side% - 1, BOTTOMV) = -1
+ elseif forest%(x% - 1, y%, HEIGHT) > forest%(x% - 1, y%, BOTTOMV) then
+ forest%(x% - 1, y% - 1, BOTTOMV) = forest%(x% - 1, y%, HEIGHT)
+ else
+ forest%(x% - 1, y% - 1, BOTTOMV) = forest%(x% - 1, y%, BOTTOMV)
+ end if
+
+ let treeheight% = forest%(x% - 1, y% - 1, HEIGHT)
+ if (forest%(x% - 1, y% - 1, LEFTV) < treeheight%) OR (forest%(x% - 1, y% - 1, TOPV) < treeheight%) OR (forest%(x% - 1, y% - 1, RIGHTV) < treeheight%) OR (forest%(x% - 1, y% - 1, BOTTOMV) < treeheight%) then
+ visible% = visible% + 1
+ end if
+ next x%
+next y%
+
+REM Loop over again and find the highest viewing distance
+let maxsc = 0
+for y% = side% to 1 step - 1
+ for x% = side% to 1 step -1
+ let treeheight% = forest%(x% - 1, y% - 1, HEIGHT)
+ let lv = 0
+ let tv = 0
+ let rv = 0
+ let bv = 0
+
+ REM Find left visibility
+ if x% = 1 then
+ lv = 0
+ else
+ lv = 0
+ do
+ lv = lv + 1
+ loop until (forest%(x% - (lv + 1), y% - 1, HEIGHT) >= treeheight%) or (x% - lv = 1)
+ end if
+
+ REM Find top visibility
+ if y% = 1 then
+ tv = 0
+ else
+ tv = 0
+ do
+ tv = tv + 1
+ loop until (forest%(x% - 1, y% - (tv + 1), HEIGHT) >= treeheight%) or (y% - tv = 1)
+ end if
+
+ REM Find right visibility
+ if x% = side% then
+ rv = 0
+ else
+ rv = 0
+ do
+ rv = rv + 1
+ loop until (forest%(x% + (rv - 1), y% - 1, HEIGHT) >= treeheight%) or (x% + rv = side%)
+ end if
+
+ REM Find bottom visibility
+ if y% = side% then
+ bv = 0
+ else
+ bv = 0
+ do
+ bv = bv + 1
+ loop until (forest%(x% - 1, y% + (bv - 1), HEIGHT) >= treeheight%) or (y% + bv = side%)
+ end if
+
+ let scenic = lv * tv * rv * bv
+ if scenic > maxsc then maxsc = scenic
+ next x%
+next y%
+
+print visible%; " visible trees"
+print maxsc; " max scenic value"
+end
