Add my not-working solution draft for day 3: day3.py

Author: FunProgramer

day3.py

@@ -0,0 +1,73 @@
+# wrong answer, but seems to work as expected up to line 3 (line_idx=2) number: 667 (number_idx: 57)
+# every line in the "engine schematic" (-> the puzzle input) has 141 characters
+LINE_LENGTH = 141
+# the "engine schematic" has 140 lines
+NUMBER_OF_LINES = 140
+
+input_lines = []
+
+
+def is_part_number(line_idx: int, number_idx: int, number_length: int):
+    if number_idx != 0:
+        if is_part_marker(input_lines[line_idx][number_idx - 1]):
+            return True
+        if line_idx != 0:
+            if is_part_marker(input_lines[line_idx - 1][number_idx - 1]):
+                return True
+        if line_idx != NUMBER_OF_LINES - 1:
+            if is_part_marker(input_lines[line_idx + 1][number_idx - 1]):
+                return True
+    if number_idx + number_length != LINE_LENGTH - 1:
+        if is_part_marker(input_lines[line_idx][number_idx + number_length]):
+            return True
+        if line_idx != 0:
+            if is_part_marker(input_lines[line_idx - 1][number_idx + number_length]):
+                return True
+        if line_idx != NUMBER_OF_LINES - 1:
+            if is_part_marker(input_lines[line_idx + 1][number_idx + number_length]):
+                return True
+    if line_idx != 0:
+        for idx in range(number_idx, number_idx + number_length):
+            if is_part_marker(input_lines[line_idx - 1][idx]):
+                return True
+    if line_idx != NUMBER_OF_LINES - 1:
+        for idx in range(number_idx, number_idx + number_length):
+            if is_part_marker(input_lines[line_idx + 1][idx]):
+                return True
+
+    return False
+
+
+# Part Marker refers all symbols except the '.'.
+# As stated in the puzzle any number that is in any way adjacent to one of these symbols is a part number.
+def is_part_marker(adjacent_char: str):
+    return not adjacent_char.isdigit() and adjacent_char != "."
+
+
+def main():
+    with open("day3_input.txt", "r") as input_file:
+        input_string = input_file.read()
+
+    global input_lines
+    input_lines = input_string.splitlines()
+    part_numbers_sum: int = 0
+
+    for line_idx, line in enumerate(input_lines):
+        number: str = ""
+        number_idx: int | None = None
+        for char_idx, char in enumerate(line):
+            if char.isdigit():
+                number += char
+                if not number_idx:
+                    number_idx = char_idx
+            elif number_idx:
+                if is_part_number(line_idx, number_idx, len(number)):
+                    part_numbers_sum += int(number)
+                number = ""
+                number_idx = None
+
+    print("Sum of part numbers:", part_numbers_sum)
+
+
+if __name__ == '__main__':
+    main()