1 files changed, 92 insertions, 0 deletions

diff --git a/src/19/part2 b/src/19/part2
new file mode 100644
index 0000000..6f056a4
--- /dev/null
+++ b/src/19/part2
@@ -0,0 +1,92 @@
+--- Part Two ---
+
+As you look over the list of messages, you realize your matching rules aren't quite right. To fix
+them, completely replace rules 8: 42 and 11: 42 31 with the following:
+
+8: 42 | 42 8
+11: 42 31 | 42 11 31
+
+This small change has a big impact: now, the rules do contain loops, and the list of
+messages they could hypothetically match is infinite. You'll need to determine how these changes
+affect which messages are valid.
+
+Fortunately, many of the rules are unaffected by this change; it might help to start by looking at
+which rules always match the same set of values and how those rules (especially rules
+42 and 31) are used by the new versions of rules 8 and 11.
+
+(Remember, you only need to handle the rules you have; building a solution that could
+handle any hypothetical combination of rules would be significantly more difficult.)
+
+For example:
+
+42: 9 14 | 10 1
+9: 14 27 | 1 26
+10: 23 14 | 28 1
+1: "a"
+11: 42 31
+5: 1 14 | 15 1
+19: 14 1 | 14 14
+12: 24 14 | 19 1
+16: 15 1 | 14 14
+31: 14 17 | 1 13
+6: 14 14 | 1 14
+2: 1 24 | 14 4
+0: 8 11
+13: 14 3 | 1 12
+15: 1 | 14
+17: 14 2 | 1 7
+23: 25 1 | 22 14
+28: 16 1
+4: 1 1
+20: 14 14 | 1 15
+3: 5 14 | 16 1
+27: 1 6 | 14 18
+14: "b"
+21: 14 1 | 1 14
+25: 1 1 | 1 14
+22: 14 14
+8: 42
+26: 14 22 | 1 20
+18: 15 15
+7: 14 5 | 1 21
+24: 14 1
+
+abbbbbabbbaaaababbaabbbbabababbbabbbbbbabaaaa
+bbabbbbaabaabba
+babbbbaabbbbbabbbbbbaabaaabaaa
+aaabbbbbbaaaabaababaabababbabaaabbababababaaa
+bbbbbbbaaaabbbbaaabbabaaa
+bbbababbbbaaaaaaaabbababaaababaabab
+ababaaaaaabaaab
+ababaaaaabbbaba
+baabbaaaabbaaaababbaababb
+abbbbabbbbaaaababbbbbbaaaababb
+aaaaabbaabaaaaababaa
+aaaabbaaaabbaaa
+aaaabbaabbaaaaaaabbbabbbaaabbaabaaa
+babaaabbbaaabaababbaabababaaab
+aabbbbbaabbbaaaaaabbbbbababaaaaabbaaabba
+
+Without updating rules 8 and 11, these rules only match three messages: bbabbbbaabaabba,
+ababaaaaaabaaab, and ababaaaaabbbaba.
+
+However, after updating rules 8 and 11, a total of 12 messages match:
+
+
+ - bbabbbbaabaabba
+ - babbbbaabbbbbabbbbbbaabaaabaaa
+ - aaabbbbbbaaaabaababaabababbabaaabbababababaaa
+ - bbbbbbbaaaabbbbaaabbabaaa
+ - bbbababbbbaaaaaaaabbababaaababaabab
+ - ababaaaaaabaaab
+ - ababaaaaabbbaba
+ - baabbaaaabbaaaababbaababb
+ - abbbbabbbbaaaababbbbbbaaaababb
+ - aaaaabbaabaaaaababaa
+ - aaaabbaabbaaaaaaabbbabbbaaabbaabaaa
+ - aabbbbbaabbbaaaaaabbbbbababaaaaabbaaabba
+
+
+After updating rules 8 and 11, how many messages completely match rule 0?
+
+