From 763f450877134498212187e963b90e9e77887e31 Mon Sep 17 00:00:00 2001
From: Greg Burri <greg.burri@gmail.com>
Date: Thu, 3 Dec 2020 09:31:37 +0100
Subject: [PATCH] Day 3
---
advent_of_code_2020.jl | 98 ++++++++++++++++++++++++++++++++++++------
1 file changed, 85 insertions(+), 13 deletions(-)
diff --git a/advent_of_code_2020.jl b/advent_of_code_2020.jl
index df49843..9e8b81c 100644
--- a/advent_of_code_2020.jl
+++ b/advent_of_code_2020.jl
@@ -1,9 +1,17 @@
### A Pluto.jl notebook ###
-# v0.12.15
+# v0.12.16
using Markdown
using InteractiveUtils
+# âââ¡ 661be9a0-353b-11eb-3598-a5b5245368cb
+html"""<style>
+main {
+ max-width: 100%;
+ margin-right: 0;
+}</style>
+"""
+
# âââ¡ f0dd4400-3313-11eb-3295-af913c2212fb
md"# Advent Of Code 2020"
@@ -56,6 +64,15 @@ struct Password
p :: String
end
+# âââ¡ bbda1c1e-347a-11eb-0e7a-756906c4c9f4
+nb_of_valid_passwords_part2(passwords) =
+ count(
+ password ->
+ (password.p[password.policy_range.start] == password.policy_char) â»
+ (password.p[password.policy_range.stop] == password.policy_char),
+ passwords
+ )
+
# âââ¡ 10f5ffa0-3474-11eb-2a36-d5c6f78f18c6
function parse_day2(lines)
line_regexp = r"^(\d+)-(\d+) ([a-z]): ([a-z]+)$"
@@ -75,17 +92,7 @@ end
# âââ¡ 6695038e-3472-11eb-1846-3b1c041be59d
nb_of_valid_passwords_part1(passwords) =
count(
- password ->
- count(==(password.policy_char), password.p) â password.policy_range,
- passwords
- )
-
-# âââ¡ bbda1c1e-347a-11eb-0e7a-756906c4c9f4
-nb_of_valid_passwords_part2(passwords) =
- count(
- password ->
- (password.p[password.policy_range.start] == password.policy_char) â»
- (password.p[password.policy_range.stop] == password.policy_char),
+ password -> count(==(password.policy_char), password.p) â password.policy_range,
passwords
)
@@ -118,7 +125,65 @@ md"**Result for part 1**: $(nb_of_valid_passwords_part1(input_day2))"
# âââ¡ de3c2f00-347b-11eb-0aec-8b776a855f6a
md"**Result for part 2**: $(nb_of_valid_passwords_part2(input_day2))"
+# âââ¡ 14e39f60-3536-11eb-0c2a-5945a1ccb638
+md"## Day 3"
+
+# âââ¡ 1b7ec110-3536-11eb-04c4-af7b43e6c68e
+function parse_day3(lines)
+ map(==("#"), hcat(split.(lines, "")...))'
+end
+
+# âââ¡ a6abdfc0-3536-11eb-3003-c13c39952d78
+function nb_trees_encountered(area :: AbstractArray{Bool, 2}, moves = [(1, 3)])
+ map(moves) do (di, dj)
+ foldl(
+ ((j, sum), i) -> (mod1(j + dj, size(area, 2)), sum + area[i, j]),
+ 1:di:size(area, 1),
+ init = (1, 0)
+ )[2]
+ end
+end
+
+# âââ¡ 1814fa70-353c-11eb-20de-51f779e98bdb
+nb_trees_encountered_part2(area) = nb_trees_encountered(area, [(1, 1), (1, 3), (1, 5), (1, 7), (2, 1)])
+
+# âââ¡ da0fb260-3536-11eb-2c09-8f1b322090ab
+let
+ test_input =
+ """..##.......
+ #...#...#..
+ .#....#..#.
+ ..#.#...#.#
+ .#...##..#.
+ ..#.##.....
+ .#.#.#....#
+ .#........#
+ #.##...#...
+ #...##....#
+ .#..#...#.#"""
+ trees = parse_day3(split(test_input, '\n'))
+ n_part1 = nb_trees_encountered(trees)
+ n_part2 = nb_trees_encountered_part2(trees)
+
+ md"
+Test 1, part 1: $(n_part1 == [7])
+
+Test 1, part 2: $(prod(n_part2) == 336)
+ "
+end
+
+# âââ¡ c003a5ae-3537-11eb-00b2-e58a970471ac
+input_day3 = parse_day3(readlines("data/day03.txt"))
+
+# âââ¡ ab7f3260-3539-11eb-3f97-fde10d5d852b
+md"
+**Result for part 1**: $(nb_trees_encountered(input_day3))
+
+**Result for part 2**: $(nb_trees_encountered_part2(input_day3) |> prod)
+"
+
# âââ¡ Cell order:
+# ââ661be9a0-353b-11eb-3598-a5b5245368cb
# ââf0dd4400-3313-11eb-3295-af913c2212fb
# ââ0b7b8920-3314-11eb-2cfb-7d20c0967e67
# â â877b32e0-3315-11eb-0e96-650b19da693e
@@ -128,10 +193,17 @@ md"**Result for part 2**: $(nb_of_valid_passwords_part2(input_day2))"
# ââc7dcdae0-33b1-11eb-2cab-fbc06c8ef76b
# ââ5d9712b0-3472-11eb-1423-719331dfe52f
# â âb9144990-3473-11eb-0ba9-59f3fe6ddbc0
+# â âbbda1c1e-347a-11eb-0e7a-756906c4c9f4
# â â10f5ffa0-3474-11eb-2a36-d5c6f78f18c6
# â â6695038e-3472-11eb-1846-3b1c041be59d
-# â âbbda1c1e-347a-11eb-0e7a-756906c4c9f4
# ââa0cfb670-3474-11eb-1a05-c12914658a0a
# ââ4a629040-347a-11eb-2aae-6f37a4c89168
# ââ5825aa50-347a-11eb-37ca-811e1b59d37a
# ââde3c2f00-347b-11eb-0aec-8b776a855f6a
+# ââ14e39f60-3536-11eb-0c2a-5945a1ccb638
+# â â1b7ec110-3536-11eb-04c4-af7b43e6c68e
+# â âa6abdfc0-3536-11eb-3003-c13c39952d78
+# â â1814fa70-353c-11eb-20de-51f779e98bdb
+# ââda0fb260-3536-11eb-2c09-8f1b322090ab
+# ââc003a5ae-3537-11eb-00b2-e58a970471ac
+# ââab7f3260-3539-11eb-3f97-fde10d5d852b
--
2.49.0