AdventOfCode-Day4.ls

# Day Four in Node for fun
# http://adventofcode.com/2017/day/4/

require! "fs"
require! 'prelude-ls': {lines, words, zip, map, filter, unique}
length = (.length)
sort   = (.split('').sort().join(''))

input   = map words, lines (fs.read-file-sync "input.txt", 'utf-8')
sorted  = map ((x) -> map ((y) -> sort y), x), input
zippers = zip (map length, sorted), (map length, map unique, sorted)
console.log (length (filter ((x) -> x[0] is x[1]), zippers))

--- Part Two ---
For added security, yet another system policy has been put in place. Now, a valid passphrase must contain no two words that are anagrams of each other - that is, a passphrase is invalid if any word's letters can be rearranged to form any other word in the passphrase.

For example:

abcde fghij is a valid passphrase.
abcde xyz ecdab is not valid - the letters from the third word can be rearranged to form the first word.
a ab abc abd abf abj is a valid passphrase, because all letters need to be used when forming another word.
iiii oiii ooii oooi oooo is valid.
oiii ioii iioi iiio is not valid - any of these words can be rearranged to form any other word.
Under this new system policy, how many passphrases are valid?