Add solutions for day two and three

day3.cr

@@ -0,0 +1,37 @@
+require "advent"
+
+def letter_score(letter : Char)
+  if letter.uppercase?
+    letter.ord - 'A'.ord + 1 + 26
+  else
+    letter.ord - 'a'.ord + 1
+  end
+end
+
+INPUT = input(2022, 3).lines
+
+def part1(input)
+  input = input.map do |line|
+    first = line[0, line.size//2]
+    second = line[line.size//2, line.size//2]
+    {first.chars.to_set, second.chars.to_set}
+  end
+  input.sum do |a,b|
+    puts (a & b)
+    (a & b).to_a.map do |l|
+      puts letter_score(l)
+      letter_score(l)
+    end.sum
+  end
+end
+
+def part2(input)
+  input
+    .map(&.chars.to_set)
+    .in_groups_of(3, Set(Char).new)
+    .map(&.reduce { |l,r| l & r  }.sum { |l| letter_score l })
+    .sum
+end
+
+puts part1(INPUT.clone)
+puts part2(INPUT.clone)