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ipynb/AdventUtils.ipynb

@@ -21,7 +21,7 @@
    "source": [
     "from collections import Counter, defaultdict, namedtuple, deque, abc\n",
     "from dataclasses import dataclass, field\n",
-    "from itertools   import permutations, combinations, cycle, chain, islice\n",
+    "from itertools   import permutations, combinations, cycle, chain, islice, filterfalse\n",
     "from itertools   import count as count_from, product as cross_product, takewhile\n",
     "from typing      import *\n",
     "from statistics  import mean, median\n",
@@ -173,7 +173,6 @@
    "outputs": [],
    "source": [
     "answers = {} # `answers` is a dict of {puzzle_number: answer}\n",
-    "\n",
     "unknown = 'unknown'\n",
     "\n",
     "class answer:\n",
@@ -754,7 +753,12 @@
     "    \n",
     "class HCounter(Counter):\n",
     "    \"\"\"A Counter, but it is hashable.\"\"\"\n",
-    "    def __hash__(self): return hash(tuple(sorted(self.items())))"
+    "    def __hash__(self): return hash(tuple(sorted(self.items())))\n",
+    "\n",
+    "class EqualityIsIdentity:\n",
+    "    \"\"\"A mixin to say that objects of this class are equal only if they are identical.\"\"\"\n",
+    "    def __hash__(self): return id(self)\n",
+    "    def __eq__(self, other): return self is other"
    ]
   },
   {
@@ -766,7 +770,7 @@
     "class Graph(defaultdict):\n",
     "    \"\"\"A graph of {node: [neighboring_nodes...]}. \n",
     "    Can store other kwd attributes on it (which you can't do with a dict).\"\"\"\n",
-    "    def __init__(self, contents, **kwds):\n",
+    "    def __init__(self, contents=(), **kwds):\n",
     "        self.update(contents)\n",
     "        self.default_factory = list\n",
     "        self.__dict__.update(**kwds)"