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-rwxr-xr-xday06/part242
1 files changed, 42 insertions, 0 deletions
diff --git a/day06/part2 b/day06/part2
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+++ b/day06/part2
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+#!/usr/bin/env ruby
+
+def get_depth_to(hsh, elm, to)
+ n = 0
+ loop do
+ break if elm == to
+ n += 1
+ elm = hsh[elm]
+ end
+ n
+end
+
+def get_hier(hsh, elm)
+ hier = [elm]
+ loop do
+ break if elm == "COM"
+ elm = hsh[elm]
+ hier << elm
+ end
+ hier
+end
+
+input = $stdin.readlines.map(&:strip).map{|x|x.split(")")}
+
+objects = {}
+
+input.each do |line|
+ objects[line[1]] = line[0]
+end
+
+me_hier = get_hier(objects, "YOU")
+santa_hier = get_hier(objects, "SAN")
+
+lca = nil
+me_hier.each do |obj|
+ if santa_hier.include?(obj) then
+ lca = obj
+ break
+ end
+end
+
+puts get_depth_to(objects, "YOU", lca) + get_depth_to(objects, "SAN", lca) - 2