commit 095a4b10cc6f23e0a2cc0ae3981c353cb0a29de9
parent a6c1a5f1a201893f9d07a4ce634763a50d26f0b0
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date: Mon, 9 Dec 2024 06:58:08 +0000
Day 8 reference and solutions
Diffstat:
2 files changed, 98 insertions(+), 0 deletions(-)
diff --git a/2024/day08.nim b/2024/day08.nim
@@ -0,0 +1,85 @@
+# Copyright (c) 2024, Natacha Porté
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+from std/math import gcd
+from std/sequtils import addUnique, concat, deduplicate, toSeq
+
+# Read input file
+
+type Point = tuple
+ x, y: int
+
+func process_data(data: seq[string]): array[62, seq[Point]] =
+ var i: int
+ for y in 0 ..< len(data):
+ for x in 0 ..< len(data[y]):
+ case data[y][x]
+ of '.':
+ continue
+ of '0' .. '9':
+ i = ord(data[y][x]) - ord('0')
+ of 'A' .. 'Z':
+ i = ord(data[y][x]) - ord('A') + 10
+ of 'a' .. 'z':
+ i = ord(data[y][x]) - ord('a') + 36
+ else:
+ assert(false)
+
+ result[i].add((x, y))
+
+let
+ data = stdin.lines().toSeq()
+ nlines = len(data)
+ ncols = len(data[0])
+ coord = process_data(data)
+
+# Puzzle 1
+
+func antinodes(s: seq[Point], corner: Point): seq[Point] =
+ for i in 0 ..< len(s):
+ for j in 0 ..< len(s):
+ if i == j:
+ continue
+ let n = (x: 2*s[i].x - s[j].x, y: 2*s[i].y - s[j].y)
+ if n.x >= 0 and n.y >= 0 and n.x <= corner.x and n.y <= corner.y:
+ result.addUnique(n)
+
+func all_antinodes(d: openArray[seq[Point]], corner: Point): seq[Point] =
+ for s in d:
+ result = deduplicate(concat(result, antinodes(s, corner)))
+
+echo "Puzzle 1: ", len(all_antinodes(coord, (ncols - 1, nlines - 1)))
+
+# Puzzle 2
+
+func antinodes2(s: seq[Point], corner: Point): seq[Point] =
+ for i in 0 ..< len(s):
+ for j in 0 ..< len(s):
+ if i == j:
+ continue
+ let
+ ld = (x: s[i].x - s[j].x, y: s[i].y - s[j].y)
+ g = gcd(ld.x, ld.y)
+ d = (x: ld.x div g, y: ld.y div g)
+ var p = s[i]
+ while p.x >= 0 and p.y >= 0 and p.x <= corner.x and p.y <= corner.y:
+ result.addUnique(p)
+ p.x += d.x
+ p.y += d.y
+
+func all_antinodes2(d: openArray[seq[Point]], corner: Point): seq[Point] =
+ for s in d:
+ result = deduplicate(concat(result, antinodes2(s, corner)))
+
+echo "Puzzle 2: ", len(all_antinodes2(coord, (ncols - 1, nlines - 1)))
diff --git a/2024/ref/day08.txt b/2024/ref/day08.txt
@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............
+\ No newline at end of file
