Add 2022 and 2023

1 files changed, 36 insertions, 0 deletions

diff --git a/2022/day4.rb b/2022/day4.rb
new file mode 100644
index 0000000..a700986
--- /dev/null
+++ b/2022/day4.rb
@@ -0,0 +1,36 @@
+def range(s)
+  n1, n2 = s.split('-')
+  return n1.to_i .. n2.to_i
+end
+
+def read_pairs(filename)
+  retval = []
+  File.open(filename) do |file|
+    file.readlines.each do |line|
+      elf1, elf2 = line.split(',')
+      retval << [range(elf1), range(elf2)]
+    end
+  end
+  return retval
+end
+
+def range_included(r1, r2)
+  return (r2.include?(r1.first) && r2.include?(r1.last)) || (r1.include?(r2.first) && r1.include?(r2.last))
+end
+
+def range_overlaps(r1, r2)
+  return (r2.include?(r1.first) || r2.include?(r1.last)) || (r1.include?(r2.first) || r1.include?(r2.last))
+end
+
+def part1(filename)
+  read_pairs(filename).map { |pairs|
+    range_included(pairs[0], pairs[1])
+  }.select { |x| x }.count
+end
+
+def part2(filename)
+  read_pairs(filename).map { |pairs|
+    range_overlaps(pairs[0], pairs[1])
+  }.select { |x| x }.count
+
+end