Day 3

diff --git a/advent_of_code_2020.jl b/advent_of_code_2020.jl
index df49843..9e8b81c 100644 (file)
--- 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
 
+# ╔═╡ 661be9a0-353b-11eb-3598-a5b5245368cb
+html"""<style>
+main {
+       max-width: 100%;
+       margin-right: 0;
+}</style>
+"""
+
 # ╔═╡ f0dd4400-3313-11eb-3295-af913c2212fb
 md"# Advent Of Code 2020"
 
@@ -56,6 +64,15 @@ struct Password
        p :: String
 end    
 
+# ╔═╡ bbda1c1e-347a-11eb-0e7a-756906c4c9f4
+nb_of_valid_passwords_part2(passwords) =
+       count(
+               password ->
+                       (password.p[password.policy_range.start] == password.policy_char) ⊻
+                       (password.p[password.policy_range.stop] == password.policy_char),
+               passwords
+       )
+
 # ╔═╡ 10f5ffa0-3474-11eb-2a36-d5c6f78f18c6
 function parse_day2(lines)
        line_regexp = r"^(\d+)-(\d+) ([a-z]): ([a-z]+)$"
@@ -75,17 +92,7 @@ end
 # ╔═╡ 6695038e-3472-11eb-1846-3b1c041be59d
 nb_of_valid_passwords_part1(passwords) =
        count(
-               password ->
-                       count(==(password.policy_char), password.p) ∈ password.policy_range,
-               passwords
-       )
-
-# ╔═╡ bbda1c1e-347a-11eb-0e7a-756906c4c9f4
-nb_of_valid_passwords_part2(passwords) =
-       count(
-               password ->
-                       (password.p[password.policy_range.start] == password.policy_char) ⊻
-                       (password.p[password.policy_range.stop] == password.policy_char),
+               password -> count(==(password.policy_char), password.p) ∈ password.policy_range,
                passwords
        )
 
@@ -118,7 +125,65 @@ md"**Result for part 1**: $(nb_of_valid_passwords_part1(input_day2))"
 # ╔═╡ de3c2f00-347b-11eb-0aec-8b776a855f6a
 md"**Result for part 2**: $(nb_of_valid_passwords_part2(input_day2))"
 
+# ╔═╡ 14e39f60-3536-11eb-0c2a-5945a1ccb638
+md"## Day 3"
+
+# ╔═╡ 1b7ec110-3536-11eb-04c4-af7b43e6c68e
+function parse_day3(lines)     
+       map(==("#"), hcat(split.(lines, "")...))'
+end
+
+# ╔═╡ 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
+
+# ╔═╡ 1814fa70-353c-11eb-20de-51f779e98bdb
+nb_trees_encountered_part2(area) = nb_trees_encountered(area, [(1, 1), (1, 3), (1, 5), (1, 7), (2, 1)])
+
+# ╔═╡ 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
+
+# ╔═╡ c003a5ae-3537-11eb-00b2-e58a970471ac
+input_day3 = parse_day3(readlines("data/day03.txt"))
+
+# ╔═╡ 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)
+"
+
 # ╔═╡ Cell order:
+# ╟─661be9a0-353b-11eb-3598-a5b5245368cb
 # ╟─f0dd4400-3313-11eb-3295-af913c2212fb
 # ╟─0b7b8920-3314-11eb-2cfb-7d20c0967e67
 # ╠═877b32e0-3315-11eb-0e96-650b19da693e
@@ -128,10 +193,17 @@ md"**Result for part 2**: $(nb_of_valid_passwords_part2(input_day2))"
 # ╟─c7dcdae0-33b1-11eb-2cab-fbc06c8ef76b
 # ╟─5d9712b0-3472-11eb-1423-719331dfe52f
 # ╠═b9144990-3473-11eb-0ba9-59f3fe6ddbc0
+# ╠═bbda1c1e-347a-11eb-0e7a-756906c4c9f4
 # ╠═10f5ffa0-3474-11eb-2a36-d5c6f78f18c6
 # ╠═6695038e-3472-11eb-1846-3b1c041be59d
-# ╠═bbda1c1e-347a-11eb-0e7a-756906c4c9f4
 # ╟─a0cfb670-3474-11eb-1a05-c12914658a0a
 # ╟─4a629040-347a-11eb-2aae-6f37a4c89168
 # ╟─5825aa50-347a-11eb-37ca-811e1b59d37a
 # ╟─de3c2f00-347b-11eb-0aec-8b776a855f6a
+# ╟─14e39f60-3536-11eb-0c2a-5945a1ccb638
+# ╠═1b7ec110-3536-11eb-04c4-af7b43e6c68e
+# ╠═a6abdfc0-3536-11eb-3003-c13c39952d78
+# ╠═1814fa70-353c-11eb-20de-51f779e98bdb
+# ╟─da0fb260-3536-11eb-2c09-8f1b322090ab
+# ╟─c003a5ae-3537-11eb-00b2-e58a970471ac
+# ╟─ab7f3260-3539-11eb-3f97-fde10d5d852b

diff --git a/data/day03.txt b/data/day03.txt
new file mode 100644 (file)
index 0000000..26d1b5b
--- /dev/null
+++ b/data/day03.txt
@@ -0,0 +1,323 @@
+..#......###....#...##..#.#....
+.#.#.....#.##.....###...##...##
+..#.#..#...........#.#..#......
+..#......#..........###........
+...#..###..##.#..#.......##..##
+......#.#.##...#...#....###....
+..........##.....##..##......#.
+......#...........#............
+#....#..........#..............
+.#........##.............###.##
+....#.........#.......#.#....##
+#.#..#..#..#.......#...#....##.
+.#........#......#.##.......#..
+..#.....#####.....#....#..#..##
+.......#..##.......#......#.###
+..#.#...#......#.##...#........
+##...................#...##..#.
+......#...#.##...##.#......#..#
+.#.................#..##...#...
+...#.....#.......##.....#.#....
+.......#.#......#.....#..#..##.
+..........#........#...........
+..#.#..........................
+.#.##..#.#...#...#.........#...
+.....#....#.....#..#.....#.....
+...#.#.#.....#.#..#.......#..#.
+.....#...###...##...#......##..
+#.###......#.#...#.#.#..###....
+#.....#..##......#..........#.#
+#...............#........#.#..#
+.....#..#.........#......##.#..
+.....#.##.##..#..##............
+...#......##...............#.#.
+.#..#.#............##.#........
+#.....#..###.............##.#..
+...##..#.#..#...........#..#...
+#....#.........#.#.............
+##.#.........#..###......#.#..#
+...#...#......#.#.#.##..#.##...
+.....##............#.##.##..#..
+....#................#.##..#..#
+...#..#.......#...#..#........#
+....#...#...#................#.
+....##...............#.#...#...
+.#.....###...#.......#.##......
+....######.#..............###.#
+.#..#.........##...............
+................##.#..#....###.
+.......#............#.#..#..#..
+......#.#...............##.#...
+...#..####.#...#..#..#......#..
+....#.#...#.....#.........#..##
+.##..#...#......##....##.#.#...
+.##.#.........##...#....#......
+..#.#..#...#.#..#.......#...#.#
+.........#..#.....##..#........
+..#......#..##.....#..#...###..
+..#...#....#.#..#..#.#.#..#.#..
+...#..#####.....#......#.......
+#.#............#......#..#...#.
+.........#..........###.......#
+......#....#..#.##.#......#..#.
+...........##.#....#.#..#......
+..#...................#..#.#...
+#....##.............##....#...#
+##..#....#.........#..........#
+....#.#.#...#..#........#.##..#
+...............#...#..##..#....
+.##.......#.......#...........#
+#.........................##...
+#........#.#..#..##..####.#....
+...................##.....###..
+.#.......#..#......#......#...#
+..#.........#...#..........#...
+..........#......#....#........
+.#......#..#...#..#...##....##.
+...#.#..#..#......#.....##.####
+.......#.#....#.......#........
+#...#.#...##..##.#......#......
+.#.........#...................
+...#..........#.#......#.......
+...#.....##....#..........#....
+.#..........##..#..#..##....#.#
+.##.#..........#...#.##.......#
+#...###....#..#.#...#..#.......
+..................##...........
+..#...##.#...........#....#.##.
+..#......#..##..#....##..#...#.
+..#....#.....#.##..#.......#..#
+#...#....#..#.#....#......##...
+.......##..#..........#........
+..#.............##.#.....#...#.
+...............#....#...#...##.
+##...........#.......#.##......
+#..#...........#.........#.....
+....###.............###.##..##.
+.........#.#.....###.......#...
+..#.##....#.#..........#....#..
+#........#....##...#..#........
+......#..........###..#.#......
+.....#.#......##.....#..##...#.
+.#.......#......#...#...#...#.#
+.#..........##.......#.....##.#
+###.#...#....#.....#...#......#
+..#.#.#..#.##.#..#.............
+.....#.........................
+.#..###..#...#...#..#..#...#.#.
+#................##...##.##....
+......#...#...#..........#...#.
+..........#.....##.............
+..#.#......#........#.......#..
+........##.............#.......
+.......#......#.##.#..#........
+#.#.#....#........#..........#.
+##..##......#..#..#.....#.#..##
+##..#..........#...............
+#.....##...#.#......#.......#.#
+#.....#...#....#..#.....##.....
+##..........#.#.....#....#...##
+..##.###..#.....#.......#...#..
+.#.#.......#......###........#.
+.#..............#.#..###.......
+.#....#..##.........#..#.#.....
+....#....#.#....#..#.......##.#
+#.......#.......#.........#....
+...#....#....#.....##..#..#.#.#
+........#....#...........#.....
+.#......##.#.#.##..............
+#..#.#.....##........#........#
+##...#.#.......##.......#...#..
+#...#.....#.##...##.#.....#....
+....#..##...#........#.#...#...
+...#....#.#.#..###...##.#.....#
+......#..#.....#..#........##..
+.......#.....#.#.........#.#..#
+..#.......#.#.#.#.#....#.##...#
+.#...#........#..##..#......#..
+.#..#............#...#..#.#....
+...##......#......#............
+..#...#.#.....#.....#..##.#....
+.#......#.#......#..#.#........
+..#..........##...#.#.....#..#.
+#...#.....#..#...#.............
+..##.................#....#....
+.#....#.......#..##....#......#
+.#....###............##....##.#
+##..#........#..#...#.......#..
+.....#.....#.#.#.##.........#..
+.......#..#....#...#...#.......
+...#...#...#.#.#..#.#.....#....
+#.#........#..#.##..#..###.....
+..................#..#.........
+#.#.....#..##.........#.......#
+###..#.......#..............#..
+......#..#.....###..........#..
+....#.#...#..#...........#.#...
+...#.....#.......#.....#.#.....
+#.....##..#......##...........#
+#...###...........##..#...#.##.
+......##.##.#...#..#....#......
+...#.#......##.#......##....#.#
+..............#.#.###.......#..
+........#....#.......##..#..###
+...#.....##.#....#......##..#.#
+..##........#.....#.#..#...#...
+.#..#.##.........#.....#...#..#
+..#..#....#...........#........
+.#...#....................#....
+##.....##....#.............#.#.
+....#.#..#.#..#.#.#..........##
+.............##.#.....#..#..#..
+.#....#.....##...#.###.........
+..#........#........#.#..###...
+.##....#...#...#.......#...#.#.
+..#...#...#..##........#..#....
+..##.#..#..#.....#......#.#..#.
+.#........#..#....#..#.........
+..#.#.....#.##..#........###.#.
+.....#.##.....##.#.............
+#.........#.......#...##...#...
+..#.##.#..#..#............#....
+.##....#..#............#.....#.
+###........##.....##.#...#.....
+#......##..##.#.#.#.#.#.#..##..
+.....###.....#....#......#....#
+........#.........##...#....#.#
+.#.#.....#.#..#..##......#...#.
+...#.##....#..#.###..#..##.....
+....#..........##..#..#..#..#..
+...#..#.##..#..#....#.........#
+.....#..###.#.....#.....#..#...
+......#...#....#.##...#.#......
+.#.###..##.....##.##......##...
+.....#.#...........#.#.........
+#........#...#..#......##.#....
+..#.......##....##....#.##.#..#
+...###.#.........#......#.....#
+..#.##..#....#.....##...#.##...
+....##.##.............#...#....
+##..#...#..#..#..#.............
+.....#.....#.....#.............
+...#.##.......#..#.#.....#....#
+#.....##.........#......##.....
+.....##..........#..#...#..#...
+#...###....#.......#...##......
+.#....#..#......#.....#...#.#..
+#........#.#.#...#.....###.#.##
+##...#...##..#..#....#.........
+....#............#..#.....#....
+#......#.........##....#.......
+.#..#..#........#.............#
+.##..........#......#.......#..
+#............#..#....#.........
+....#.#.....#.##...#.....#.#...
+...#.#..#...##..#...#.#.#......
+#....#..#.........##..#.#.#..##
+.#...#..............#.......#..
+#...#.....#.#........##......##
+...#....##.####.#.........#.#.#
+....###.#..#............#.#..#.
+....#......#...#......##.#.#.#.
+.....#..#.#.##.#...##..........
+##..#...#.#...###.............#
+....#...#..#.....#.#..#..#..#..
+#..........####......#.....###.
+.........#........#.##.#...#...
+.........#..........#.#..###...
+.....##........##.........#...#
+..##....#...#.......##.........
+.....#.#......##....#...#...#..
+.##..#..##.....................
+.......#...#..#..#...##....#...
+.#...#.......###...#..#..#.....
+.......#.....##.##.#.......#..#
+.##......#...#....#..#......##.
+.##....#..#....#...#...#.......
+.........##..#..#.#.#.....##...
+...#..............#..#.....####
+.#.#.#..#.......#.......#......
+..#.#......#..........#........
+.#...#.#..#.......#..#..#..#...
+.......##.#...#..#....#.....#..
+.##...##....##...#........####.
+....#.#..##....#...#....#.#....
+.....#.....#..#..#.#.##..#.....
+..#....#..............#....#...
+..#.#.#.....##.#.....#..##.....
+....#.....#....#...#...#..#.#..
+#...#...........#..#..#........
+...#.#..#.........##.#...#..##.
+......#.#.........#.#...#......
+......#..##.###......##.#....#.
+.....#...#..#.......#..........
+.#...#.......#.....###......#..
+...........##.....#..#..#....#.
+..#....#..#...#......#.......#.
+..#...#...#.#..#....#...#......
+.......#....###.####...###.#...
+#.##.#.......#.......#....#.#.#
+.##..........#.....#..###......
+.....#...........#.##..#....#..
+........##.....#.#........##...
+#..#..#..................##....
+#...###..........#.............
+.......#.#.......#.#.......##..
+.....#.#...#....#...####.....#.
+..##.....##.......#....#.......
+##..........#...#..##....##....
+..........#..#......#........#.
+##..#....#..#....#.....##....#.
+##.##.....#...##.##.......#....
+..#..#.###.#..##.#..#..#...#...
+.#..#.....#........#...##.#....
+..#..#.....#.#......##.#.#.....
+.#..##...#.#....#...#...#.#.##.
+.........#...#....###.#.....#..
+...........###.#.#..#..#...#.#.
+##...#......##...........#..#..
+.........##..#...#.......#.....
+#......#.#..........#..#.......
+...#.................#....#....
+#....#......................##.
+##.......#..#......#.#...###.#.
+..#....#..#.#......#...........
+...#...........###.#.#.........
+..#..##.....#.....##...##......
+..#..#.#.#.#..#..#..##....#...#
+#......##.....##..##.##...#....
+#.....#.....#.#........#.......
+.#.....#.................#....#
+.###....#...#............#.#.#.
+.#...#.#......#.#..............
+....#...#......#.....#.......#.
+........#.....#..........#....#
+#..#......#...#...#.........#..
+#....#......#...##.#...#...#...
+#...#....#....#..#..#.....#..#.
+#......##..#..#.#.#..#.#.......
+..#..#...............#...##...#
+............#..............#.##
+.#.#.#......##.......#.......#.
+....#.........##.......#...###.
+.......#.#...#.#.#.......#.....
+....#..#..#...#....#.##.#.##...
+...##.##.#...#......#..........
+#.....#...#.#...#.##..##.#.....
+.......#.....#...#.#...##.#....
+.#.............#.....#....##..#
+##......#.......#...#....#.....
+.###......#.................#..
+#.#......##.........##..#......
+...#....#..........#.#.........
+..##..#.........#..............
+.....#...#..................#.#
+.............#.........#...#..#
+....#....#......#.#.......#...#
+#..#............#.#.......#...#
+..#.....#............#.........
+.#.....................###....#
+........#.####.........#.#.#...
+#...........##...#.........#..#
+...........#..#......#...#.#...
+....##...##.....#.....#........