day04

1 files changed, 32 insertions, 0 deletions

diff --git a/day04.rb b/day04.rb
new file mode 100644
index 0000000..b9335bf
--- /dev/null
+++ b/day04.rb
@@ -0,0 +1,32 @@
+d = []
+IO.foreach("day04") { |line|
+  d << line.split(/[\[\]:# ]/)
+}
+
+d.sort!
+
+g = nil
+s = nil
+zg = Hash.new 0
+zgt = Hash.new 0
+d.each { |l|
+  case l[5]
+  when "Guard"
+    g = l[7].to_i
+  when "falls"
+    s = l[3].to_i
+  when "wakes"
+    (s...l[3].to_i).each { |t|
+      zg[g] += 1
+      zgt[[g,t]] += 1
+    }
+  end
+}
+
+a = zg.max_by { |k,v| v }.first
+b = zgt.max_by { |(g,t),v| g == a ? v : 0 }[0][1]
+p a * b
+# => 131469
+
+p zgt.max_by { |k,v| v }[0].inject(:*)
+# => 96951