1 files changed, 46 insertions, 0 deletions
diff --git a/2023/day3/solve.py b/2023/day3/solve.py
new file mode 100644
index 0000000..bc84dc0
--- /dev/null
+++ b/2023/day3/solve.py
@@ -0,0 +1,46 @@
+from typing import List
+
+def is_part_number(lines:List[str], column_count: int, row_pos: int, column_start: int, column_end: int) -> bool:
+    min_column = max(column_start - 1, 0)
+    min_row = max(row_pos - 1, 0)
+    max_column = min(column_end + 1, column_count - 1)
+    max_row = min(row_pos + 1, len(lines) - 1)
+
+    for row_idx in range(min_row, max_row + 1):
+        for col_idx in range(min_column, max_column + 1):
+            char = lines[row_idx][col_idx]
+            if char != "." and not char.isdigit():
+                return True
+
+    return False
+
+def add_if_part_number(result: int, lines:List[str], column_count: int, row_pos: int, column_start: int, column_end: int) -> int:
+    if is_part_number(lines, column_count, row_pos, column_start, column_end):
+        result += int(lines[row_pos][column_start:column_end + 1])
+
+    return result
+
+
+data = []
+with open("input") as f:
+    for line in f.readlines():
+        data.append(line.strip())
+
+result = 0
+
+columns = len(data[0])
+for row_idx, line in enumerate(data):
+    number_start_idx = -1
+    for ii in range(columns):
+        if line[ii].isdigit():
+            if number_start_idx == -1:
+                number_start_idx = ii
+        elif number_start_idx != -1:
+            result = add_if_part_number(result, data, columns, row_idx, number_start_idx, ii - 1)
+            number_start_idx = -1
+
+    if number_start_idx != -1:
+        result = add_if_part_number(result, data, columns, row_idx, number_start_idx, columns - 1)
+
+print(result)
+