🎉 D4P1 Complete!

Author: bloopy-code

aoc_25/solutions/day04.py

@@ -1,25 +1,76 @@
 """Day 4 - Title Goes Here"""
 
 from typing import Any
-from utils.aoc_utils import input_for_day, report_results, AoCResult
+from utils.aoc_utils import report_results, AoCResult, input_for_day
 
+LooRollGrid = list[list[str]]
 
-EXAMPLE: list = []
-DATA = input_for_day(4)
+ORIGINAL_EXAMPLE: str = """..@@.@@@@.
+@@@.@.@.@@
+@@@@@.@.@@
+@.@@@@..@.
+@@.@@@@.@@
+.@@@@@@@.@
+.@.@.@.@@@
+@.@@@.@@@@
+.@@@@@@@@.
+@.@.@@@.@."""
 
+EXAMPLE: LooRollGrid = [list(x) for x in ORIGINAL_EXAMPLE.splitlines()]
+INPUT_DATA: list[str] = input_for_day(4, 2025, ff="lines")
+DATA: LooRollGrid = [list(x) for x in INPUT_DATA]
 
-def helperfunction(data: Any) -> None:
-    return None
+
+def parse_loogrid_p1(data: LooRollGrid) -> int:
+    """Navigate through the Loo Roll Grid for AOCD4P1.
+
+    Insert an extra layer of blank padding, slide a
+    3x3 window and count adjacent loo rolls.
+    If less than 4 adjacent loo rolls, count it!
+
+    Args:
+        data (LooRollGrid): List of lists, @ = loo roll.
+
+    Returns:
+        int: Count of valid positions.
+    """
+    forklift_access: int = 0
+    # add an extra padding 0 and -1
+    for row in data:
+        row.insert(0, ".")
+        row.insert(len(data[0]), ".")
+
+    # add an extra layer of padding...
+    data.insert(0, list("." * len(data[0])))
+    data.insert(len(data), list("." * len(data[0])))
+
+    # trundle through the grid
+    for row_idx, row in enumerate(data[1:-1], 1):
+        # print(ri, row[1:-1])
+        for col_idx, col in enumerate(row[1:-1], 1):
+            if "@" in col:
+                # grab a 3x3 window
+                window: LooRollGrid = [
+                    row[col_idx - 1:col_idx + 2]
+                    for row in data[row_idx - 1:row_idx + 2]
+                ]
+                # smoosh it together
+                join_window: str = "".join("".join(row) for row in window)
+                # deduct the initial @
+                num_rolls: int = join_window.count("@") - 1
+                if num_rolls < 4:
+                    forklift_access += 1
+    return forklift_access
 
 
 @report_results
 def solveday(data: Any) -> AoCResult:
-    p1: int = 0
+    p1: int = parse_loogrid_p1(data)
     p2: int = 0
     return p1, p2
 
 
-expected_test_results: AoCResult = (0, 0)
+expected_test_results: AoCResult = (13, 0)
 
 
 def tests(test_input: Any) -> None: