aoc-all

commit 02255f39187cc8f74350c0725f841f21e7c3c4fa
parent b7a2baf0e8efee1f2774ea4072e0b364645a5e9d
Author: Natasha Kerensikova <natgh@instinctive.eu>
Date:   Mon,  2 Dec 2024 18:10:36 +0000

Day 2 reference and solutions
Diffstat:
A
2024/day02.nim
 | 
60
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
2024/ref/day02.txt
 | 
6
++++++

2 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/2024/day02.nim b/2024/day02.nim
@@ -0,0 +1,60 @@
+# 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 allIt, filter, map, mapIt, toSeq, zip
+from std/strutils  import parseInt, splitWhitespace
+
+# Read input file
+
+let data = stdin.lines().toSeq().mapIt(it.splitWhitespace().map(parseInt))
+
+# First puzzle
+
+func deltas(s: seq[int]): seq[int] =
+  zip(s[1 .. ^1], s[0 .. ^2]).mapIt(it[0] - it[1])
+
+func isSafe(d: seq[int]): bool =
+  (allIt(d, it < 0) or allIt(d, it > 0)) and allIt(d, abs(it) <= 3)
+
+echo "Puzzle 1: ", len(data.map(deltas).filter(isSafe))
+
+# Second puzzle
+# 611 is too low
+
+func dampenIndex(s: seq[int], iinc, idec, idelta: var int) =
+  iinc = 0
+  idec = 0
+  idelta = 0
+  for i in 1 .. len(s) - 1:
+    if iinc == 0 and s[i] <= s[i-1]:
+      iinc = i
+    if idec == 0 and s[i] >= s[i-1]:
+      idec = i
+    if idelta == 0 and abs(s[i] - s[i-1]) > 3:
+      idelta = i
+    if iinc > 0 and idec > 0 and idelta > 0:
+      break
+
+func isDampenedSafe(s: seq[int]): bool =
+  var iinc, idec, idelta = 0
+  dampenIndex(s, iinc, idec, idelta)
+  for i in @[iinc, iinc-1, idec, idec-1, idelta, idelta-1]:
+    if i > 0 and isSafe(deltas(s[0 .. i-1] & s[i + 1 .. ^1])):
+      return true
+
+func isSafe2(s: seq[int]): bool =
+  let d = deltas(s)
+  result = isSafe(d) or isSafe(d[1 .. ^1]) or isDampenedSafe(s)
+
+echo "Puzzle 2: ", len(data.filter(isSafe2))
diff --git a/2024/ref/day02.txt b/2024/ref/day02.txt
@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9