11module Day21
22
33using AdventOfCode2024
4-
4+ using Memoize
55
66function day21 (input:: String = readInput (joinpath (@__DIR__ , " .." " data" " day21.txt"
7- numerical_keypad = [' #' ' #' ' #' ' #' ' #'
8- ' #' ' 7' ' 8' ' 9' ' #'
9- ' #' ' 4' ' 5' ' 6' ' #'
10- ' #' ' 1' ' 2' ' 3' ' #'
11- ' #' ' .' ' 0' ' A' ' #'
12- ' #' ' #' ' #' ' #' ' #'
13- directional_keypad = [' #' ' #' ' #' ' #' ' #'
14- ' #' ' .' ' ^' ' A' ' #'
15- ' #' ' <' ' v' ' >' ' #'
16- ' #' ' #' ' #' ' #' ' #'
17- layer1 = generate_instructions (" 029A"
18- layer2 = reduce (vcat, [generate_instructions (x, directional_keypad) for x ∈ layer1])
19- end
20-
21- # function calculate_instructions(keypad::Matrix{Char}, from::Char, to::Char)
22- # start = findall(x -> x == from, keypad)[1]
23- # goal = findall(x -> x == to, keypad)[1]
24- # dirs = (('v', [1, 0]), ('^', [-1, 0]), ('>', [0, 1]), ('<', [0, -1]))
25- # visited = zeros(Bool, size(keypad)...)
26- # current = [(start, "")]
27- # while !isempty(current)
28- # for (elem, st) ∈ current
29- # if elem == goal
30- # return st
31- # end
32- # visited[elem] = true
33- # end
34- # new_current = []
35- # while !isempty(current)
36- # elem, st = pop!(current)
37- # for (c, dir) ∈ dirs
38- # neighcoord = CartesianIndex((elem.I .+ dir)...)
39- # if keypad[neighcoord] != '#' && !visited[neighcoord]
40- # push!(new_current, (neighcoord, st * c))
41- # end
42- # end
43- # end
44- # current = new_current
45- # end
46- # end
47-
48- function from_to (keypad:: Matrix{Char} , from:: Char , to:: Char )
49- start = findall (x -> x == from, keypad)[1 ]
50- goal = findall (x -> x == to, keypad)[1 ]
51- # dirs = (('v', [1, 0]), ('^', [-1, 0]), ('>', [0, 1]), ('<', [0, -1]))
7+ data = split (rstrip (input), " \n "
8+ numpad = Dict {Char,Tuple{Int,Int}} (
9+ ' A' => (4 , 3 ),
10+ ' 0' => (4 , 2 ),
11+ ' 1' => (3 , 1 ),
12+ ' 2' => (3 , 2 ),
13+ ' 3' => (3 , 3 ),
14+ ' 4' => (2 , 1 ),
15+ ' 5' => (2 , 2 ),
16+ ' 6' => (2 , 3 ),
17+ ' 7' => (1 , 1 ),
18+ ' 8' => (1 , 2 ),
19+ ' 9' => (1 , 3 )
20+ )
21+ dirpad = Dict {Char,Tuple{Int,Int}} (
22+ ' A' => (1 , 3 ),
23+ ' ^' => (1 , 2 ),
24+ ' <' => (2 , 1 ),
25+ ' v' => (2 , 2 ),
26+ ' >' => (2 , 3 )
27+ )
28+ numpad_graph = create_graph (numpad, (4 , 1 ))
29+ dirpad_graph = create_graph (dirpad, (1 , 1 ))
5230
53- diff = goal - start
54- if diff[1 ] >= 0
55- x = ' v'
56- else
57- x = ' ^'
31+ p1, p2 = 0 , 0
32+ for d ∈ data
33+ p1 += solve (d, 3 , numpad_graph, dirpad_graph, true ) * parse (Int, d[1 : end - 1 ])
34+ p2 += solve (d, 26 , numpad_graph, dirpad_graph, true ) * parse (Int, d[1 : end - 1 ])
5835 end
59- if diff[2 ] > 0
60- y = ' >'
61- else
62- y = ' <'
63- end
64- return unique ([repeat (x, abs (diff[1 ])) * repeat (y, abs (diff[2 ])), repeat (y, abs (diff[2 ])) * repeat (x, abs (diff[1 ]))])
36+ return [p1, p2]
6537end
6638
67- # function code_numerical(code::String, keypad::Matrix{Char})
68- # instructions = ""
69- # from = 'A'
70- # for to ∈ code
71- # instructions *= calculate_instructions(keypad, from, to) * 'A'
72- # from = to
73- # end
74- # return instructions
75- # end
76-
77- # function code_directional(code::String, keypad::Matrix{Char})
78-
79- # end
80-
81- # function generate_instructions(code::String, keypad::Matrix{Char})
82- # instructions = ""
83- # from = 'A'
84- # for to ∈ code
85- # instructions *= calculate_instructions(keypad, from, to) * 'A'
86- # from = to
87- # end
88- # return instructions
89- # end
90-
91- function generate_instructions (code:: String , keypad:: Matrix{Char} )
92- instructions = Vector {String} ()
93- from = ' A'
94- for to ∈ code
95- parts = from_to (keypad, from, to)
96- if isempty (instructions)
97- for instr ∈ parts
98- push! (instructions, instr * ' A'
99- end
100- end
101- if length (parts) > 1
102- cp = copy (instructions)
103- end
104- for (i, _) ∈ enumerate (instructions)
105- instructions[i] *= parts[1 ] * ' A'
106- end
107- if length (parts) > 1
108- for (i, _) ∈ enumerate (cp)
109- push! (instructions, cp[i] * parts[2 ] * ' A'
39+ function create_graph (keypad, forbidden_coord)
40+ graph = Dict {Char,Dict{Char,String}} ()
41+ for key ∈ keys (keypad)
42+ graph[key] = Dict {Char,String} ()
43+ end
44+ for (k1, (x1, y1)) ∈ keypad
45+ for (k2, (x2, y2)) ∈ keypad
46+ path = repeat (" <" max (0 , y1- y2)) * repeat (" v" max (0 , x2- x1)) * repeat (" ^" max (0 , x1- x2)) * repeat (" >" max (0 , y2- y1))
47+ if forbidden_coord == (x1, y2) || forbidden_coord == (x2, y1)
48+ path = reverse (path)
11049 end
50+ graph[k1][k2] = path * ' A'
11151 end
11252 end
113- return instructions
53+ return graph
11454end
11555
56+ @memoize function solve (sequence, iterations, numpad_graph, dirpad_graph, first)
57+ iterations == 0 && return length (sequence)
58+ prev = ' A'
59+ total = 0
60+ graph = first ? numpad_graph : dirpad_graph
61+ for c ∈ sequence
62+ total += solve (graph[prev][c], iterations - 1 , numpad_graph, dirpad_graph, false )
63+ prev = c
64+ end
65+ return total
66+ end
11667
11768end # module
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