advent_of_code_2022

commit 76957adbbe41092c3a00cb022c3ca865e6433bfd
parent 25de54a3a55bb34d9111fb6915cef329d0896296
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date:   Wed, 14 Dec 2022 08:45:01 -0800

Post-solution code cleanup.

I was being lazy about parsing parts 1 and 2 separately so I rewrote the
parsing and solving to be more DRY. Along the way I learned that `|>`
is higher precedence than `==`, which surprised me.

Diffstat:
M
src/day_13.jl
 | 
25
++++++++-----------------

1 file changed, 8 insertions(+), 17 deletions(-)
diff --git a/src/day_13.jl b/src/day_13.jl
@@ -63,33 +63,24 @@ comparesides(left::Int, right::Vector{<:Any}) = comparesides([left], right)
 comparesides(left::Vector{<:Any}, right::Int) = comparesides(left, [right])
 
 """
-Read the input and return a list of pairs of lists.
+Read the input and return a list of packets.
 """
 function parse_input(input)
-    map(
-        (x, y) -> (x, y),
-        map(eval ∘ Meta.parse, input[1:3:end]),
-        map(eval ∘ Meta.parse, input[2:3:end])
-    )
+    map(eval ∘ Meta.parse, Iterators.filter(x->x!="", input))
 end
 
 function part_1(input)
-    sum(findall(map(x->comparesides(x[1], x[2]), parse_input(input)) .== "right"))
+    packetorder = map(x->comparesides(x[1], x[2]),
+                      Iterators.partition(parse_input(input), 2))
+    (packetorder .== "right") |> findall |> sum
 end
 @assert part_1(example) == 13
 @info part_1(input)
 
-# Redoing my parsing function for part 2
-function parse_input2(input)
-    [
-        map(eval ∘ Meta.parse, Iterators.filter(x -> x != "", input));
-        [ [[2]], [[6]] ]
-    ]
-end
-
 function part_2(input)
-    packets = parse_input2(input)
-    sort!(packets, lt = (x,y)->comparesides(x, y) == "right")
+    packets = parse_input(input)
+    append!(packets, [ [[2]], [[6]] ])
+    sort!(packets, lt = (x, y)->comparesides(x, y) == "right")
     findfirst(==([[2]]), packets) * findfirst(==([[6]]), packets)
 end
 @assert part_2(example) == 140