solution to day 3

3/engine.py

@@ -0,0 +1,58 @@
+from aocd.models import Puzzle
+from aocd import submit
+from dataclasses import dataclass
+import math
+import re
+
+
+def parse_input(input_data: str) -> dict:
+    """
+    Parse input and filter
+    - first get positions of all numbers in field
+    - read their value if there is an adjacent symbol
+    Assumptions to greatly simplify the task (thx reddit):
+    - No number touches more than one symbol
+    - No non-star symbol touches exactly two numbers
+    """
+
+    # convert input into a 2d array for easier parsing
+    field = [line for line in input_data.split("\n")]
+
+    # get coordinates of numbers
+    nums = {
+        (i, char): []
+        for i in range(140)
+        for char in range(140)
+        if field[i][char] not in "01234566789."
+    }
+
+    # for each row in field
+    for i, row in enumerate(field):
+        # for each number in row
+        for n in re.finditer(r"\d+", row):
+            edge = {
+                (i, char)
+                for i in (i - 1, i, i + 1)
+                for char in range(n.start() - 1, n.end() + 1)
+            }
+            for o in edge & nums.keys():
+                nums[o].append(int(n.group()))
+    return nums
+
+
+if __name__ == "__main__":
+    # get puzzle and parse data
+    puzzle = Puzzle(year=2023, day=3)
+
+    # parse_input(puzzle.input_data)
+    nums = parse_input(puzzle.input_data)
+
+    # part a:
+    answer_a = sum(sum(p) for p in nums.values())
+    print(f"{answer_a}")
+    submit(answer_a, part="a", day=3, year=2023)
+
+    # part b:
+    answer_b = sum(math.prod(p) for p in nums.values() if len(p) == 2)
+    print(f"{answer_b}")
+    submit(answer_b, part="b", day=3, year=2023)