ruby solution

02/02.rb

@@ -0,0 +1,18 @@
+input = File.readlines("input.txt")
+
+part1 = 0
+part2 = 0
+for line in input do
+	policy, password = line.split(': ')
+	counts, character = policy.split(' ')
+	n1, n2 = counts.split('-').map(&:to_i)
+	if password.count(character) >= n1 && password.count(character) <= n2
+		part1 += 1
+	end
+	if (password[n1-1] == character) ^ (password[n2-1] == character)
+		part2 += 1
+	end
+end
+
+puts "Part 1: #{part1}"
+puts "Part 2: #{part2}"