From e06e6a5162ba5f0857eea2286edcc59d91e70df0 Mon Sep 17 00:00:00 2001
From: Botond Hende <nettingman@gmail.com>
Date: Sat, 7 Dec 2024 13:16:29 +0100
Subject: 2024 day6 solve2
---
2024/day6/solve2.py | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 78 insertions(+)
create mode 100644 2024/day6/solve2.py
diff --git a/2024/day6/solve2.py b/2024/day6/solve2.py
new file mode 100644
index 0000000..faaf88a
--- /dev/null
+++ b/2024/day6/solve2.py
@@ -0,0 +1,78 @@
+import sys
+
+def traverse(room: list[list[str]], guard_current_row: int, guard_current_col: int, direct: tuple[int, int], check_for_loop: bool) -> bool:
+ row_count = len(room)
+ col_count = len(room[0])
+ previous_directions: list[list[list[tuple[int, int]]]] = []
+ for _ in range(row_count):
+ previous_directions.append([])
+ for _ in range(col_count):
+ previous_directions[-1].append([])
+
+ while True:
+ if not check_for_loop:
+ room[guard_current_row][guard_current_col] = "X"
+ else:
+ if direct in previous_directions[guard_current_row][guard_current_col]:
+ return True
+
+ previous_directions[guard_current_row][guard_current_col].append(direct)
+
+ new_row_idx = guard_current_row + direct[0]
+ new_col_idx = guard_current_col + direct[1]
+
+ if new_row_idx < 0 or new_row_idx >= row_count or new_col_idx < 0 or new_col_idx >= col_count:
+ break
+
+ if room[new_row_idx][new_col_idx] == "#":
+ dir_idx = directions.index(direct)
+ if dir_idx == len(directions) - 1:
+ dir_idx = 0
+ else:
+ dir_idx += 1
+ direct = directions[dir_idx]
+ else:
+ guard_current_row = new_row_idx
+ guard_current_col = new_col_idx
+
+ return False
+
+lines = []
+with open("input") as f:
+ for line in f.readlines():
+ lines.append(list(line.strip()))
+
+found_guard = False
+guard_row_idx = None
+guard_col_idx = None
+direction = None
+
+directions = [(-1, 0), (0, 1), (1, 0), (0, -1)]
+
+for line_idx, line in enumerate(lines):
+ for icon_idx, guard_icon in enumerate(("^", ">", "v", "<")):
+ if guard_icon in line:
+ guard_row_idx = line_idx
+ guard_col_idx = line.index(guard_icon)
+ direction = directions[icon_idx]
+ found_guard = True
+ break
+
+ if found_guard:
+ break
+
+if not found_guard:
+ sys.exit("Could not found guard.")
+
+traverse(lines, guard_row_idx, guard_col_idx, direction, False)
+
+count = 0
+for row_idx, line in enumerate(lines):
+ for col_idx, char in enumerate(line):
+ if char == "X":
+ lines[row_idx][col_idx] = "#"
+ if traverse(lines, guard_row_idx, guard_col_idx, direction, True):
+ count += 1
+ lines[row_idx][col_idx] = "X"
+
+print(count)
--
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