commit a6c1a5f1a201893f9d07a4ce634763a50d26f0b0
parent d2eee7c7e30e27621c13477db7d4003568447014
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date: Sun, 8 Dec 2024 07:46:52 +0000
Day 7 reference and solutions
Diffstat:
2 files changed, 77 insertions(+), 0 deletions(-)
diff --git a/2024/day07.nim b/2024/day07.nim
@@ -0,0 +1,68 @@
+# 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 concat, filter, foldl, map, mapIt, toSeq
+from std/strutils import parseInt, split, splitWhitespace
+
+# Read input file
+
+func parse_line(l: string): seq[int] =
+ let halves = l.split(": ")
+ assert len(halves) == 2
+ result = concat(@[parseInt(halves[0])], halves[1].splitWhitespace().map(parseInt))
+
+let data = stdin.lines().toSeq().map(parse_line)
+
+# First puzzle
+# 354 is too low
+# 465092164034 is too low
+
+func is_good(target, acc: int, terms: seq[int]): bool =
+ if len(terms) == 0:
+ result = acc == target
+ elif acc > target:
+ result = false
+ else:
+ result = is_good(target, acc * terms[0], terms[1 .. ^1]) or
+ is_good(target, acc + terms[0], terms[1 .. ^1])
+
+func line_is_good(l: seq[int]): bool =
+ is_good(l[0], l[1], l[2 .. ^1])
+
+echo "Puzzle 1: ", data.filter(line_is_good).mapIt(it[0]).foldl(a + b)
+
+# Second puzzle
+# 54566744875618 is too low
+# 68296976306294 is too low
+
+func int_cat(a, b: int): int =
+ var f = 10
+ while f <= b:
+ f *= 10
+ result = a * f + b
+
+func is_good2(target, acc: int, terms: seq[int]): bool =
+ if len(terms) == 0:
+ result = acc == target
+ elif acc > target:
+ result = false
+ else:
+ result = is_good2(target, int_cat(acc, terms[0]), terms[1 .. ^1]) or
+ is_good2(target, acc * terms[0], terms[1 .. ^1]) or
+ is_good2(target, acc + terms[0], terms[1 .. ^1])
+
+func line_is_good2(l: seq[int]): bool =
+ is_good2(l[0], l[1], l[2 .. ^1])
+
+echo "Puzzle 2: ", data.filter(line_is_good2).mapIt(it[0]).foldl(a + b)
diff --git a/2024/ref/day07.txt b/2024/ref/day07.txt
@@ -0,0 +1,9 @@
+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20
