Add day 7

1 files changed, 39 insertions, 0 deletions

diff --git a/07/a.rb b/07/a.rb
new file mode 100644
index 0000000..d7a69db
--- /dev/null
+++ b/07/a.rb
@@ -0,0 +1,39 @@
+rules = {}
+gold_producing = {}
+lines = 0
+File.readlines('input.txt').each do |line|
+  lines += 1
+  line.chomp!
+  bag, contents = line.split 'bags contain' 
+  bag.strip!
+  rules[bag] = []
+  contents.split(', ').map do |content|
+    match = /^(\d+) ([\w\s]+) bags?\.?$/.match(content.strip)
+    if match
+      color = match[2]
+      rules[bag].push color
+
+      if color == 'shiny gold'
+        gold_producing[bag] = true
+      end
+    end
+
+  end
+end
+
+changed = true
+while changed
+  changed = false
+  rules.each do |bag, productions|
+    if !gold_producing[bag]
+      productions.each do |subbag|
+        if gold_producing[subbag]
+          gold_producing[bag] = true
+          changed = true
+        end
+      end
+    end
+  end
+end
+
+puts gold_producing.size