Solution to problem 12 in Python

src/Year_2015/P12.py

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+# --- Day 12: JSAbacusFramework.io ---
+
+# Santa's Accounting-Elves need help balancing the books after a recent order.
+# Unfortunately, their accounting software uses a peculiar storage format.
+# That's where you come in.
+
+# They have a JSON document which contains a variety of things: arrays
+# ([1,2,3]), objects ({"a":1, "b":2}), numbers, and strings. Your first job is
+# to simply find all of the numbers throughout the document and add them
+# together.
+
+# For example:
+
+#     [1,2,3] and {"a":2,"b":4} both have a sum of 6.
+#     [[[3]]] and {"a":{"b":4},"c":-1} both have a sum of 3.
+#     {"a":[-1,1]} and [-1,{"a":1}] both have a sum of 0.
+#     [] and {} both have a sum of 0.
+
+# You will not encounter any strings containing numbers.
+
+# What is the sum of all numbers in the document?
+
+import json
+import re
+
+with open("files/P12.txt") as f:
+    doc = f.read()
+
+digits = r"[\d-]+"
+
+
+def part_1() -> None:
+    ans = sum(map(int, re.findall(digits, doc)))
+    print(f"The sum of all numbers is {ans}")
+
+
+# --- Part Two ---
+
+# Uh oh - the Accounting-Elves have realized that they double-counted
+# everything red.
+
+# Ignore any object (and all of its children) which has any property with the
+# value "red". Do this only for objects ({...}), not arrays ([...]).
+
+#     [1,2,3] still has a sum of 6.
+#     [1,{"c":"red","b":2},3] now has a sum of 4, because the middle object is
+# ignored.
+#     {"d":"red","e":[1,2,3,4],"f":5} now has a sum of 0, because the entire
+# structure is ignored.
+#     [1,"red",5] has a sum of 6, because "red" in an array has no effect.
+
+
+def ignore_red(dic: dict[str, int]) -> dict[str, int]:
+    return {} if "red" in dic.values() else dic
+
+
+def part_2() -> None:
+    # use the object_hook from the json library
+    doc2 = str(json.loads(doc, object_hook=ignore_red))
+
+    ans = sum(map(int, re.findall(digits, doc2)))
+    print(f"The corrected sum of all numbers is {ans}")
+
+
+if __name__ == "__main__":
+    part_1()
+    part_2()