completed Day 2 part 1

Author: matthew-js-porter

day2/README.txt

@@ -0,0 +1,19 @@
+--- Day 2: Password Philosophy ---
+Your flight departs in a few days from the coastal airport; the easiest way down to the coast from here is via toboggan.
+
+The shopkeeper at the North Pole Toboggan Rental Shop is having a bad day. "Something's wrong with our computers; we can't log in!" You ask if you can take a look.
+
+Their password database seems to be a little corrupted: some of the passwords wouldn't have been allowed by the Official Toboggan Corporate Policy that was in effect when they were chosen.
+
+To try to debug the problem, they have created a list (your puzzle input) of passwords (according to the corrupted database) and the corporate policy when that password was set.
+
+For example, suppose you have the following list:
+
+1-3 a: abcde
+1-3 b: cdefg
+2-9 c: ccccccccc
+Each line gives the password policy and then the password. The password policy indicates the lowest and highest number of times a given letter must appear for the password to be valid. For example, 1-3 a means that the password must contain a at least 1 time and at most 3 times.
+
+In the above example, 2 passwords are valid. The middle password, cdefg, is not; it contains no instances of b, but needs at least 1. The first and third passwords are valid: they contain one a or nine c, both within the limits of their respective policies.
+
+How many passwords are valid according to their policies?