Add Advent 2021 - day 20.

2021/day20/p.rkt

@@ -0,0 +1,61 @@
+#lang racket/base
+(require racket/match)
+
+(define algo (read-line))
+(define _ (read-line))
+
+(define shash (make-hash))
+(define max-dimension 0)
+
+(for ([t (in-lines)] [i (in-naturals)])
+  (set! max-dimension (add1 i))
+  (for ([c t] [j (in-naturals)])
+    (hash-set! shash (cons j i) c)))
+
+(define number-of-pixels 9)
+(define (pixel-positions n)
+  (match n
+    [8 (values -1 -1)]
+    [7 (values 0 -1)]
+    [6 (values 1 -1)]
+    [5 (values -1 0)]
+    [4 (values 0 0)]
+    [3 (values 1 0)]
+    [2 (values -1 1)]
+    [1 (values 0 1)]
+    [0 (values 1 1)]))
+
+(define (replicant-finding sh start size other-positions)
+  (for*/hash ([x (in-range start (+ start size))] [y (in-range start (+ start size))])
+    (let ([index
+           (for/sum ([i number-of-pixels])
+             (let-values ([(dx dy) (pixel-positions i)])
+               (arithmetic-shift
+                (if (char=? (hash-ref sh (cons (+ x dx) (+ y dy)) other-positions) #\#)
+                    1
+                    0)
+                i)))])
+      (values (cons x y) (string-ref algo index)))))
+
+(define (display-image sh start size)
+  (for ([y (in-range start (+ start size))])
+    (for ([x (in-range start (+ start size))])
+      (display (hash-ref sh (cons x y))))
+    (printf "~n")))
+
+(define (enhance sh times start size other-positions)
+  (let* ([start (- start 2)]
+         [size (+ size 4)]
+         [new-hash (replicant-finding sh start size other-positions)])
+    ;(display-image new-hash start size)
+    (if (> times 1)
+        (enhance new-hash (sub1 times) start size (if (char=? other-positions #\#) (string-ref algo #x1ff) (string-ref algo 0)))
+        new-hash)))
+
+(define (lit-pixels sh)
+  (length (remove* '(#\.) (hash-values sh))))
+
+; part 1
+(lit-pixels (enhance shash 2 0 max-dimension #\.))
+; part 2
+(lit-pixels (enhance shash 50 0 max-dimension #\.))

2021/day20/test1.txt

@@ -0,0 +1,7 @@
+..#.#..#####.#.#.#.###.##.....###.##.#..###.####..#####..#....#..#..##..###..######.###...####..#..#####..##..#.#####...##.#.#..#.##..#.#......#.###.######.###.####...#.##.##..#..#..#####.....#.#....###..#.##......#.....#..#..#..##..#...##.######.####.####.#.#...#.......#..#.#.#...####.##.#......#..#...##.#.##..#...##.#.##..###.#......#.#.......#.#.#.####.###.##...#.....####.#..#..#.##.#....##..#.####....##...##..#...#......#.#.......#.......##..####..#...#.#.#...##..#.#..###..#####........#..####......#..#
+
+#..#.
+#....
+##..#
+..#..
+..###

2021/day20/test2.txt

@@ -0,0 +1,102 @@
+####...###.###.##.##.##..###..##.#.##.#...####..##...#..#..#....#..#..##.##..#.#.####.######.#..#.##..##....#.####.##...#.#..#.####.#.#.#..###.##..#.#.#.#...#.....###.#.#...#..#....#######....#..#...###.##.........#.#.##.#........##...#..##.......####.#.#.#.#.#.####..#..........#.##......##......###.#..##.#.#.....###.#..#...###.##........#..#.##.#.###.#..#####..##..#..#.#.#...###..##..#.###.##...#.##.#.....#.#..........#..##.#########.#.#..##.#.##..######.....####...###..###.#..##########.#.#.....###.##.##.
+
+#.#...#..##..########...##....#.#.###.#.##.##...#..###.#.##.#.#..#..##..###....#..##.##....#...##.#.
+.###.#..#.#.#..##.##.#.####..##.#...#.###...#.#....#.#.###..#.#..###...##..######..#..#..#####......
+##.#.###.#.#..###...##..###.#.#..#....#...#..#.....##..###.###.######.####.#.#...##.#.##.####..#.##.
+...#..##...########.##..#..#...#...#...##.#..#.#..#.##..##.#..#...#.##........#.#.#.######..#..#.#..
+.....###....#.##....####..#.#.#.###.###.##.#.#.###..#..##.#...##.###..#.##..##.##..#.#....####..#.#.
+..####..###.#..###.#.....#..#..#....#########.####.#..#.##.##..#....#.....#.#.#..#.#..#..###.##...##
+###.#..#####...####.##...####...#.#####.##...##.####.###...###...##...#..#.#.######.##....#....##..#
+...#...#.#.###..#.#..#.#.####..####.#..#...#...#.#...#...#.....##..#.....#.#.#....#####.##..#.#..###
+##...##..###..#..#...#..#..#.####...#.##.###.#.#....#..##....#.....#.##.###.###.#.....#####.#...#...
+.##.#..#..#..#.##.#.##.###.###....##.#.#...#####.#..##..#....###..#.#...##.###.#..#.####..##..######
+#.#..####.###.#####.###.##....##..####.##.##.#########.........#.#.....####.##.....#.#...##.#....##.
+.#..#.#.#..#.#.#.#.#..###....##.#.##.#....#.##.#....#####.#..###...##......#..#.#.##..##..######..##
+..##.####.##.....#.#######..##.##...##.####.####.##...####..#.###....#..###..##..#.####....###..##..
+#.#....#...#.#.#..#.#..#...#####..#.#..###.#.##...#####.....##.#....#.#.##.#..#.#..###...#.#.#..#..#
+##.#.#..#.###.###.##.####....###.#.##.#.#.##...###.##.#.#...##.#.##..#.##.##.#.#....#.....#.#.###...
+.#.##.#....#.#.#.###.##..#######.###..#...#...#####.###.#.#.###..###...###.######.#.#....#...#####.#
+####..#..####.#......####..##...####...##.#.######.###.###.#.#.#.#....##.#######....##.#..####..##.#
+..##.#..###...##....##.###.#.#.#....#..##..###..##..##..#.####..#....#.#.####..#..##.#..#....#..##.#
+.#..#.#..##.###....#...####...##.##..#.#..##.##.##.###....##...##.....#.###......###..#.#..###....#.
+###.#...#.##...####.#.##.###..#.....##.#.#...#.#..###.##..###.#..#.#.#.#.#####.#.####.##..####..##..
+.....#.#..#.##...#..#.....#.###.##########.##.....#..####.##.##.###.##..#.##..#....#.#..##...###.#..
+#..#.##.#.#.#..#....##########.###..#.#...#.##...#####..#..##..#..####.......###..#..#.###..###.##.#
+###.#..##..##..####...#.####..##.######....#..#...#..##...#####.####.##.####...######..#..##...##..#
+..##.#####...#.##..###...###.#......#.#.######.#...####.####.##.##....##..##.#.#..####.#####.######.
+..##..#.#..###..#.....####..#.####.##.#.####.##.....####..##..#...###.#...###...#.#.#........##...#.
+.#.###.##.##.#.##.##..#.#.###...##..#..#..#.##.#.#..##.#.#.#.##....##....#.#......#....#..#....##.#.
+#####.#.###...###.#..#.##.###...###.##.##........#.###.#...##.###.#...###.##.##..#.##.###..####.###.
+#....####.#..#.###....##.#.##..##.....#..#...#...##.#..#.#...#..##.#..##..######.##..####.##...#.#..
+..#.#..#..##.##...##.###...#...###..#.##..#.#####..#.#.##.#######.##.#.#..##..####.....#####..#.#.##
+#.#.....#.#.##.##.##.##......#...##.##.###..#...#.#........##....#.#.....#.##.###....#..###..#..#.##
+..#.#.####..#.##...#.###.##....#.##.#########.###...##...##.#.#....#...#...##.....###.##.........#..
+###.##.#.#...#...##...##...##.##.#..#.#....##.#.##..#..##.#.##.##..#.#.####.###.#.##.##....#.###.##.
+###..#.######.#.###.##.###..##.#..######..###.....###......#.##..##..#.....##..##.##..#.#....##.##.#
+..##.#....#.........##.##.#.#..####..##.#......#....#...##.#####..##........##....#.###...###.###..#
+##...###.#.#..#.#..##.#.##.####....###....##.#####.##....#.##...##..#.....#....#...######..#.#...###
+.##.##.#..###.#.###.#.#.###...####.##.#.#.#.####.#...####.##..###.#...##..##.####..###.#.#..##..##..
+#..#...#####.##...#...##..###.#.#....#.#...#########..##.....##.#.#...###......#.##.########..#.##..
+##..##.##.......##..##........###.#....#.####.#..#.#.###....#.#.#.#.###.#.#..##..##...##.#.....#....
+....#..##...#####...##..#.###....##.##..##.#....#....#..#.#...#.#####...#..##.#.##...#.#...####...##
+..##..####.##....#.###.####...###.#.##.##...#..##..#.###.###.#.#.######.#..#####......##..#.###.#.#.
+#..#.#....#...###.#.#....##.###..#....##..####.#..#.#####.#.###.######...#..###.##..####.#...##.#..#
+..#.##.##.#.##........#..##.....#.#.#.#.##.##..#..##...#.##...#...#.##.###..###.....##..#....#.#..##
+###.##...##.#.#...##...####.###.#...####..###...#.##.#..#.#.###......#.#...###..#.####.##.#.#.####..
+#.#.##.##...#..##..#....#.##..##......###..###...####..##...###.#.##.##..##...####.#.....#.##.##...#
+.....#...#.##.#..#.##.#.####.#######......##.#..#...##..#...#.###.###.#.##.#.##..#.##.##.#..#.###..#
+####...#####..##....##.#####...#...#...##.....##..###..#...###..#...#...##.###..###.#####...##.#....
+#..###...###....#.#.#.######.###..####..#####...###..###..###....##.#.##..#.##..##..#.###.#####.....
+#.#.##.#.####..#####.###.#..#####.#..#.#.#..#.##....##.#.#.#.#.###.###..###...#####.#.##.#.#.#..#...
+.#.#...#..#.##.#..####..###.#..#.########.####......#...##..#####..#...#.#..###..#.#....####....#..#
+##.###.###..#..##.#..#...#..####..#.###..##....#.#...######.##....##...#....#.........####.#.###.#..
+.##..####.##.#.#..####...#.##..##.##..###...#.....##...#......#....##...#####..#####.#.#.#...#..##..
+.#...##.#.###.#.#.##....###..###.##.#.##.....###.####.......#.#.#.#....##.#..#..#..#####..#....#.#.#
+..#.##.###.###.................###.#...#...#.##.#.###..###..#..##..#.#..###..##.#.##.#.##.##.##.#...
+###.#...#..#...###.......###.#.#..#####.####.#..#...##...#####..#........###.#..#.#######..####.#.##
+...#.##.#####.#...##.###...##.#..#..##.##.##..#.#.#.#.###...#.##..#.##.##.#.#.##...##.###....#..#.##
+##.#.####.##.#..#####.#.#...######.###.#.#.##.##...##.#.##.#..#...##.##.#..#...#..#..#..#..#.##.#...
+#.#######.#..#.##..#..#.#..#..####....#.#..#..#...#.....####...#..#.......#..#...##..##.##.##..#.#..
+..##.#.####.#.#.#......########..#..#.....###.#.####.#..#####.##..####.#.###....##.#.#..#.##..#####.
+.##.#.##.#.#..#.#.#.#...#########...#####..#...###.#.##..##.#..##...###.##.#.#.#.#...####.#.#.####.#
+.#####.####..##.##....#.#.#...######.#.#..#.#.#....#.#....##.#..#.###..#..#.####...###..##.#.#.#.#..
+.##..#..###.######.#.#.#..######.##..#..#.######....###.##..#####.....####.#.#.#...##.###.#...##.##.
+.#.####..##.#..#.#..#.###.##.#....##..#.#..#####.##.##...#..####..###..#........#.##..##.####...###.
+..##..###.#.###.#...##.#.##.##.#######..##.#....#.####.#...####...####.###.##.##...##.#..#.#....#..#
+.##..#.######..#.#.##.....######.#####......###.#....###.##.#.###.#..#.#.###.#.####...####.##.....##
+.####....#.##.##.#.#....#.##.#..#...##.....#..##......#..#######..#.##.###.#..#.###.####..###.#.#..#
+..#.##.#.#..##..####....#######.##...#.##.....#.#.##....#.###.#.#..#.###.#.....#.####.#.....##.#...#
+##...#.##..##.#.........#..#..#######.##.#..###.#.###..#.##.#..#...#..#..#.##.##.#..###.###...##.##.
+...#.#..###..#.##.#####.#.##...#.##..###.#...#...#.##....#####..#####....###..#.####.#...#.###.....#
+..#.####..#..#.#..#.######...##.##...##...#.#.#.....#..#...##..#.############.###.####....###..###..
+#.#...#.#.##..##..#.#..#...####.##.##.#.#.#.##..##.#.#.....#....#...#...#.###.#.#####..##.###...#..#
+.#....#.##..###.#..#.###.#..#.#..##..##.......########.#...#...#####.#...#..#..##.....#.##.....####.
+#.#####.#.##.###.#.#....#.#.###...##.#.....##..##..#.#####..#.#.##.#..###..##...#.#.##.#.#.....#.#..
+..###...#.#.......#.#......##.#..#.#.#.#.#...#.###.##...####....######......#...#####..###.##...#..#
+#..#...#..##..#...#...####.#...#....#####.#...#...#.#.....##...##..#...#....#..#####...#.....##...#.
+#.####.#...#...#..##...##....#...#.#.##.##.##...##..##.#..#..#.##.##.##.#.##......#.#...##.....#...#
+.#..####..###........#####...#....#.####..##..#####.##.###..#..###...##..##...##.....#..#.#.###.#...
+.#....#.####....#....##..#.#.######.#######.#.##.###.###...#.#....##..#..####.###.#....###...#.#....
+...###..##.#.##..#.#.#####.######.#..######.##...#.##.#..##.###.#.......#..#...#.###...##..####.##.#
+#....###....#..#####.#..#...###..##.##...##.###...#...#....#..#...#..####.#.####...#..##....#...#.##
+#.####.###...#..#.####...#..#.##.###.#.##.#....#..##.#.#...##.#..#.##.##..#####..#..#...###...#.####
+#.##.##..##.##......#.#.##...###.####.###.####.#...##...#.#...###..###.######.#####....###.####.#...
+##..#.###....#.#..###.#..##..###.#..##..#####.#.###..#.#...##.#.#.#.####....##...##....###.#.#.#..##
+...#.###.###..###.##...#.###.#.####.##..#.#..###...#..##.######.#.#..###..#.##...##.###....##.#...#.
+#..#.#..#.#..#.#.#.#.#..##..#....#..###.###.#...#.#####.#..#..#.#....#.#.#.#....##.##..#...##......#
+...#...##....#....#.##.######.#...#.....#.##..#....#..##.#.........###..#..#..#.##.##...#.#..#######
+##.##..#..#.#..#.#.######.##...####...#...#..#..##.#......#.#....#.###..#.###...#...#...#.##...###..
+#.####.#.##....##..###....#.##.#.##....####.#.#.##.#....#..#..###...#.....##.##....####..###........
+..#..##...##.#...#..#.#..###....##...#...####.....####....###..##..##..##.###..#.....######.........
+.###.###.##.#...#.##..##.#.##.#.#..#.#..###.#....###.#..##.###....#...#####.###..###.####..#.#...##.
+..##.#.#.####.#..#..###.##.#####.#.#....##..#.#.##..##..#...###.#...#...#...#...#..#..##.#...##...##
+......###..#####...##..##.#.....###.#...#..###..####..##..#..#####..##..#..##..####.#..#.........#..
+###............#.#.......###..#..##..#.#####.#.##.########.##..####.#.########..#.###.....#.####.#.#
+.#.....#....##..#.##..#...#.#.##.##..#.##...#.##.#..#......##.....##..##.#..##.###...###....#.##.###
+..#...###....##....#.#...###.###..##.##...#.#.#.#..#....###.#.##.....##.#..#.#######.#.###...###....
+##.#.#.#.#...####.##..#.#####..######..#.#...#.#.........#....##.....#....#.###....#.#.#..#...##....
+.......#.#.#..#....####.##.##.#.......#.#.###..#..#..#..##.#.#.##.#.##.#.#.#..##.#..###..#.###...##.
+..##.#.#..##.##...#..#..#..#..###..#.##..#.##..#..#....#....#.##.##.###.##.###..##.......######.###.
+##.#.#.#.#.#..###...###..####...##..##.###.#..#..####.#...###..#.##.##.#.#.###..###.#.#.#...###..#..
+..##...####......##..#..#..#...#...#..##...######.##......#.#.#....#.#.#.#..#..##.#...#.########...#
+####.##.#.#.####..#.#.##.#..#...#.#.##.#....#..#.####.#.#####.###..##.#.####...##.###.#.#....#.#####