advent_of_code_2022

commit f84dd861d09545ffe1da81ca7ceb57fbf9802f30
parent cf1d38d09caf7e3ba5a892b66df4de627607fd0a
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date:   Sun,  4 Dec 2022 04:51:12 -0800

Reworked solution with cool Julia stuff I learned.

I'm still updating my solutions with cool snippets from other folks'
Julia solutions (but only after finding a solution, natch). This has
been updated to include the \div operator, Iterators.partition, and a
slick (but technically unnecessary) use of reduce.

Diffstat:
M
src/day_3.jl
 | 
15
+++++++++------

1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/src/day_3.jl b/src/day_3.jl
@@ -19,8 +19,8 @@ function get_compartments(rucksack)
     rucksack = Vector{UInt8}(rucksack)
     rucksack = map(x->(x>Int('Z')) ? x-Int('a')+1 : x-Int('A')+27,
                    rucksack)
-    (rucksack[1:Integer(length(rucksack)/2)],
-     rucksack[Integer(length(rucksack)/2+1):end])
+    (rucksack[1:end÷2],
+     rucksack[end÷2+1:end])
 end
 
 # This is written to assume there's only one item in both compartments
@@ -41,14 +41,17 @@ end
 # operator `...`.
 
 # This function takes a group of rucksacks (in string format) and finds the
-# value of the "badge"
+# value of the "badge". Also, you can splat the input to intersect (and I did
+# that for my original solution), but I saw somebody else call reduce and that
+# feels worth cribbing (even if it's no more efficient).
 function get_rucksacks_badge(rucksacks)
-    intersect(map(x->union(x...), map(get_compartments, rucksacks))...)[1]
+    reduce(intersect,
+           map(x->union(get_compartments(x)...),rucksacks))[1]
 end
 
 function part_2(input)
-    sum([get_rucksacks_badge(input[i:i+2]) 
-         for i = 1:3:length(input)])
+    sum(map(get_rucksacks_badge,
+            Iterators.partition(input, 3)))
 end
 @assert part_2(example) == 70
 @info part_2(input)