From a35861c5a8288b3948ebe2c81fa9ec45d0009894 Mon Sep 17 00:00:00 2001
From: Ben Charlton <ben@spod.cx>
Date: Tue, 22 Dec 2020 23:22:53 +0000
Subject: [PATCH] day 19

---
 19/19.py | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 19/19.py

diff --git a/19/19.py b/19/19.py
new file mode 100644
index 0000000..cd6e69d
--- /dev/null
+++ b/19/19.py
@@ -0,0 +1,93 @@
+#!/usr/bin/python3
+
+import sys, re
+
+def is_integer(n):
+    try:
+        float(n)
+    except ValueError:
+        return False
+    else:
+        return float(n).is_integer()
+
+def process_rules(rules, id):
+    rule = rules[id]
+    check = rule.split(" ")
+    r = "("
+    p = ""
+    q = ""
+    for c in check:
+        if is_integer(c):
+            r += process_rules(rules, c)
+        elif c == '"a"':
+            r += "a"
+        elif c == '"b"':
+            r += "b"
+        elif c == '|':
+            r += "|"
+    r += p
+    r += ")" 
+    r += q
+
+    return r
+
+def process_rules2(rules, id):
+    rule = rules[id]
+    check = rule.split(" ")
+    r = "("
+    p = ""
+    q = ""
+    for c in check:
+        if is_integer(c):
+            if id == "8":
+                return "(" + process_rules2(rules, "42" ) + ")+"
+            elif id == "11":
+                x = []
+                for t in range(1,15):
+                    x.append("(" + process_rules2(rules, "42" )+"{" + str(t) + "}" +  process_rules(rules, "31" ) + "{" + str(t) + "}"+ ")")
+
+                return  "(" +  "|".join(x) + ")"
+            else:
+                r += process_rules2(rules, c)
+        elif c == '"a"':
+            r += "a"
+        elif c == '"b"':
+            r += "b"
+        elif c == '|':
+            r += "|"
+    r += p
+    r += ")" 
+    r += q
+
+    return r
+
+
+rules = {}
+r = r2 = ""
+count = count2 = 0
+for line in sys.stdin:
+    line = line.rstrip()
+
+    m = re.match(r'^(\d+): (.*?)$', line)
+    if m is not None:
+        id = m.group(1)
+        rule = m.group(2)
+        rules[id] = rule
+        continue
+
+    if line == "":
+        r = "^" + process_rules(rules, "0") + "$"
+        r2 = "^" + process_rules2(rules, "0") + "$"
+
+    m = re.match(r'^([ab]+)$', line)
+    if m is not None:
+        check = re.match(r, m.group(1))
+        if check is not None:
+            count += 1
+
+        check2 = re.match(r2, m.group(1))
+        if check2 is not None:
+            count2 += 1
+
+print(1, count)
+print(2, count2)
\ No newline at end of file