Santa needs help figuring out which strings in his text file are naughty or nice.
A nice string is one with all of the following properties:
aeiou
only), like aei
, xazegov
, or aeiouaeiouaeiou
.xx
, abcdde
(dd
), or aabbccdd
(aa
, bb
, cc
, or dd
).ab
, cd
, pq
, or xy
, even if they are part of one of the other requirements.For example:
ugknbfddgicrmopn
is nice because it has at least three vowels (u...i...o...
),
a double letter (...dd...
), and none of the disallowed substrings.aaa
is nice because it has at least three vowels and a double letter, even though the letters used by different rules overlap.jchzalrnumimnmhp
is naughty because it has no double letter.haegwjzuvuyypxyu
is naughty because it contains the string xy
.dvszwmarrgswjxmb
is naughty because it contains only one vowel.How many strings are nice?
In [1]:
has3vowels=: 3 <: [: +/ e.&'aeiou'
hasDouble=: [: +./ 2 =/\ ]
noBadStrings=: -.@(+./)@((_2 ]\ 'abcdpqxy') +./@E."1 ])
isNiceString=: noBadStrings *. hasDouble *. has3vowels
input=: 'b' freads '~AoC/2015/aoc05_input.txt'
echo 'Day5 Part1: ',": +/ isNiceString &> input
Realizing the error of his ways, Santa has switched to a better model of determining whether a string is naughty or nice. None of the old rules apply, as they are all clearly ridiculous.
Now, a nice string is one with all of the following properties:
xyxy
(xy
) or aabcdefgaa
(aa
), but not like aaa
(aa
, but it overlaps).xyx
, abcdefeghi
(efe
), or even aaa
.For example:
qjhvhtzxzqqjkmpb
is nice because is has a pair that appears twice (qj
) and a letter that repeats with exactly one letter between them (zxz
).xxyxx
is nice because it has a pair that appears twice and a letter that repeats with one between, even though the letters used by each rule overlap.uurcxstgmygtbstg
is naughty because it has a pair (tg
) but no repeat with a single letter between them.ieodomkazucvgmuy
is naughty because it has a repeating letter with one between (odo
), but no pair that appears twice.How many strings are nice under these new rules? )
In [2]:
NB. http://code.jsoftware.com/wiki/Essays/Non-Overlapping_Substrings
tc =: ,&_1 {~^:a: 0:
findNonOverlapStr=: i.@#@] e. #@[ (tc@(] I. +) { _1 ,~ ]) I.@E.
hasPair2Letters=: 1 < [: >./ [: +/"1 ] findNonOverlapStr"1~ 2 ]\ ]
hasRepeatedLetter=: [: +./ ] = '55' ,~ 2&}.
isNiceString2=: hasPair2Letters *. hasRepeatedLetter
echo 'Day5 Part2: ',": +/ isNiceString2 &> input