Day A Dozen

day12/Project.toml

@@ -0,0 +1,4 @@
+name = "day12"
+uuid = "8b45b4a1-93ce-4a08-b654-2545c47524be"
+authors = ["HeNine "]
+version = "0.1.0"

day12/data/case00.txt

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+start-A
+start-b
+A-c
+A-b
+b-d
+A-end
+b-end

day12/data/case01.txt

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+dc-end
+HN-start
+start-kj
+dc-start
+dc-HN
+LN-dc
+HN-end
+kj-sa
+kj-HN
+kj-dc

day12/data/case02.txt

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+fs-end
+he-DX
+fs-he
+start-DX
+pj-DX
+end-zg
+zg-sl
+zg-pj
+pj-he
+RW-he
+fs-DX
+pj-RW
+zg-RW
+start-pj
+he-WI
+zg-he
+pj-fs
+start-RW

day12/data/case03.txt

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+TR-start
+xx-JT
+xx-TR
+hc-dd
+ab-JT
+hc-end
+dd-JT
+ab-dd
+TR-ab
+vh-xx
+hc-JT
+TR-vh
+xx-start
+hc-ME
+vh-dd
+JT-bm
+end-ab
+dd-xx
+end-TR
+hc-TR
+start-vh

day12/src/day12.jl

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+include("../../AoC2021.jl")
+
+##
+
+function parsefile(file)
+    pairs = map(eachline(file)) do line
+        split(line, "-") |>
+        p -> (p[1], p[2])
+    end
+
+    nodes = (pairs .|> ((x, y),) -> [x, y]) |>
+            (x -> vcat(x...)) |>
+            (x -> filter(x -> x ∉ ["start", "end"], x)) |>
+            unique |>
+            x -> ["start", x..., "end"]
+
+    bigcaves = map(x -> all(isuppercase.(collect(x))), nodes)
+
+    graph = zeros(Int, length(nodes), length(nodes))
+
+    for (x, y) in pairs
+        graph[findfirst(nodes .== x), findfirst(nodes .== y)] = 1
+        graph[findfirst(nodes .== y), findfirst(nodes .== x)] = 1
+    end
+
+    (nodes, bigcaves, graph)
+end
+
+function findpaths(currentnode, nodes, bigcaves, graph, visited, path)
+    path = [path..., currentnode]
+
+    if currentnode == "end"
+        return [path]
+    end
+
+    currentnodeindex = nodes .== currentnode
+
+    if currentnodeindex' * bigcaves == 0
+        visited = [visited..., currentnode]
+    end
+
+    findall(graph * currentnodeindex .> 0) .|>
+    (x -> nodes[x]) |>
+    (x -> filter(x -> x ∉ visited, x)) .|>
+    (x -> findpaths(x, nodes, bigcaves, graph, visited, path)) |>
+    (x -> vcat(x...))
+end
+
+##
+
+function task0(file)
+    (nodes, bigcaves, graph) = parsefile(file)
+
+    findpaths("start", nodes, bigcaves, graph, [], []) |> length
+end
+
+##
+
+verify(12, 1, 0, 10)
+verify(12, 1, 1, 19)
+verify(12, 1, 2, 226)
+verify(12, 1, 3, 5157)
+
+##
+
+function findpaths2(currentnode, nodes, bigcaves, graph, visited, path, visitedtwice = false)
+    path = [path..., currentnode]
+
+    if currentnode == "end"
+        return [path]
+    end
+
+    currentnodeindex = nodes .== currentnode
+
+    visitedtwice = currentnode ∈ visited || visitedtwice
+
+    if currentnodeindex' * bigcaves == 0
+        visited = [visited..., currentnode]
+    end
+
+    findall(graph * currentnodeindex .> 0) .|>
+    (x -> nodes[x]) |>
+    (x -> filter(x -> !visitedtwice && x != "start" || x ∉ visited, x)) .|>
+    (x -> findpaths2(x, nodes, bigcaves, graph, visited, path, visitedtwice)) |>
+    (x -> vcat(x...))
+end
+
+function task1(file)
+    (nodes, bigcaves, graph) = parsefile(file)
+
+    findpaths2("start", nodes, bigcaves, graph, [], []) |> length
+end
+
+##
+
+verify(12, 2, 0, 36)
+@profview verify(12, 2, 3, 144309)