Solve 2015 days 11-18.

2015/d19.py

@@ -0,0 +1,41 @@
+import sys
+from random import shuffle
+
+data = open(0).read().strip()
+
+eqs = []
+text = ""
+for line in data.splitlines():
+    if "=>" in line:
+        lhs, rhs = line.split(" => ")
+        eqs.append((lhs, rhs))
+    elif line:
+        text = line
+
+molecules = set()
+for lhs, rhs in eqs:
+    for i in range(len(text)):
+        f, t = text[:i], text[i:]
+        if t.startswith(lhs):
+            n = f + t.replace(lhs, rhs, 1)
+            molecules.add(n)
+print(len(molecules))
+
+# m = float("inf")
+# for _ in range(100000):
+#     getout = False
+#     c = str(text)
+#     for i in range(10**4):
+#         if i % 1000 == 0:
+#             shuffle(eqs)
+#         for lhs, rhs in eqs:
+#             if rhs in c:
+#                 c = c.replace(rhs, lhs, 1)
+#                 if c == "e":
+#                     if i < m:
+#                         m = i
+#                         print(i)
+#                     getout = True
+#         if getout:
+#             break
+# print(m)