commit adc17e242f8245aa0dcb43a9058d2e4f940282ea
parent ffb6e69cd1385bc1f7c42f7d7a5f841f4dabed55
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date: Thu, 12 Dec 2024 19:57:48 +0000
Day 12 references and solutions
Diffstat:
6 files changed, 133 insertions(+), 0 deletions(-)
diff --git a/2024/day12.nim b/2024/day12.nim
@@ -0,0 +1,103 @@
+# 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/sequtils import foldl, mapIt, toSeq
+from std/tables import `[]=`, getOrDefault, initTable, pairs, Table, values
+
+# Read input file
+
+let data = stdin.lines().toSeq()
+
+# Puzzle 1
+
+func reg(d: seq[string]): seq[seq[int]] =
+ let dirs = @[(-1, 0), (1, 0), (0, -1), (0, 1)]
+ result = d.mapIt(it.mapIt(0 * ord(it)))
+ var n_reg = 0
+ for start_y in 0 ..< len(d):
+ for start_x in 0 ..< len(d[start_y]):
+ if result[start_y][start_x] > 0:
+ continue
+ n_reg += 1
+ result[start_y][start_x] = n_reg
+ var queue = dirs.mapIt((start_x + it[0], start_y + it[1]))
+ while len(queue) > 0:
+ let
+ x = queue[0][0]
+ y = queue[0][1]
+ queue = queue[1 .. ^1]
+ if y < 0 or y >= len(d) or x < 0 or x >= len(d[y]) or result[y][x] > 0 or d[y][x] != d[start_y][start_x]:
+ continue
+ result[y][x] = n_reg
+ for d in dirs:
+ queue.add((x + d[0], y + d[1]))
+
+proc cost1(d: seq[seq[int]], n: int): int =
+ let dirs = @[(-1, 0), (1, 0), (0, -1), (0, 1)]
+ var area = 0
+ var peri = 0
+ for y in 0 ..< len(d):
+ for x in 0 ..< len(d[y]):
+ if d[y][x] != n:
+ continue
+ area += 1
+ for dir in dirs:
+ let
+ dx = x + dir[0]
+ dy = y + dir[1]
+ if dy < 0 or dy >= len(d) or dx < 0 or dx >= len(d[dy]) or d[dy][dx] != n:
+ peri += 1
+ result = area * peri
+# echo n, ": ", area, " * ", peri
+
+let
+ regions = reg(data)
+ n_regs = regions.mapIt(max(it)).max()
+
+echo "Puzzle 1: ", (1 .. n_regs).mapIt(cost1(regions, it)).foldl(a + b)
+
+# Puzzle 2
+
+proc inc(t: var Table[(int, int), int], x, y: int): void =
+ t[(x, y)] = t.getOrDefault((x, y), 0) + 1
+
+proc cost2(d: seq[seq[int]], n: int): int =
+ let dirs = @[(-1, 0), (1, 0), (0, -1), (0, 1)]
+ var area = 0
+ var h_corners = initTable[(int, int), int]()
+ var v_corners = initTable[(int, int), int]()
+ for y in 0 ..< len(d):
+ for x in 0 ..< len(d[y]):
+ if d[y][x] != n:
+ continue
+ area += 1
+ for dir in dirs:
+ let
+ dx = x + dir[0]
+ dy = y + dir[1]
+ if dy < 0 or dy >= len(d) or dx < 0 or dx >= len(d[dy]) or d[dy][dx] != n:
+ if dir[0] == 0:
+ v_corners.inc(x, max(y, dy))
+ v_corners.inc(x + 1, max(y, dy))
+ if dir[1] == 0:
+ h_corners.inc(max(x, dx), y)
+ h_corners.inc(max(x, dx), y + 1)
+ var corners = 0
+ for k, v in h_corners:
+ if v_corners.getOrDefault(k, 0) == v:
+ corners += v
+ result = area * corners
+# echo n, ": ", area, " * ", corners
+
+echo "Puzzle 2: ", (1 .. n_regs).mapIt(cost2(regions, it)).foldl(a + b)
diff --git a/2024/ref/day12a.txt b/2024/ref/day12a.txt
@@ -0,0 +1,4 @@
+AAAA
+BBCD
+BBCC
+EEEC
diff --git a/2024/ref/day12b.txt b/2024/ref/day12b.txt
@@ -0,0 +1,5 @@
+OOOOO
+OXOXO
+OOOOO
+OXOXO
+OOOOO
diff --git a/2024/ref/day12c.txt b/2024/ref/day12c.txt
@@ -0,0 +1,10 @@
+RRRRIICCFF
+RRRRIICCCF
+VVRRRCCFFF
+VVRCCCJFFF
+VVVVCJJCFE
+VVIVCCJJEE
+VVIIICJJEE
+MIIIIIJJEE
+MIIISIJEEE
+MMMISSJEEE
diff --git a/2024/ref/day12d.txt b/2024/ref/day12d.txt
@@ -0,0 +1,5 @@
+EEEEE
+EXXXX
+EEEEE
+EXXXX
+EEEEE
diff --git a/2024/ref/day12e.txt b/2024/ref/day12e.txt
@@ -0,0 +1,6 @@
+AAAAAA
+AAABBA
+AAABBA
+ABBAAA
+ABBAAA
+AAAAAA
