advent_of_code_2022

commit cf1d38d09caf7e3ba5a892b66df4de627607fd0a
parent d192fc570215a53f691896191f9bb005c9119134
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date:   Sun,  4 Dec 2022 04:26:07 -0800

Solution to day 3, part 2.

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

1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/src/day_3.jl b/src/day_3.jl
@@ -35,7 +35,20 @@ end
 @assert part_1(example) == 157
 @info part_1(input)
 
+# For part 2, we don't need to worry about rucksack compartments at all, but I
+# already wrote the logic to turn items into values, and reusing
+# get_compartments gave me the opportunity to learn about Julia's splat
+# operator `...`.
+
+# This function takes a group of rucksacks (in string format) and finds the
+# value of the "badge"
+function get_rucksacks_badge(rucksacks)
+    intersect(map(x->union(x...), map(get_compartments, rucksacks))...)[1]
+end
+
 function part_2(input)
-    nothing
+    sum([get_rucksacks_badge(input[i:i+2]) 
+         for i = 1:3:length(input)])
 end
+@assert part_2(example) == 70
 @info part_2(input)