2024 day15

1 files changed, 119 insertions, 0 deletions

diff --git a/2024/day15/solve2.py b/2024/day15/solve2.py
new file mode 100644
index 0000000..86e5c82
--- /dev/null
+++ b/2024/day15/solve2.py
@@ -0,0 +1,119 @@
+def get_affected_boxes_if_can_move(data: list[list[str]], current_pos: tuple[int, int],
+                                   affected_box_positions: list[tuple[int, int]], direction: tuple[int, int]) -> bool:
+    current_char = data[current_pos[0]][current_pos[1]]
+    if current_char == "]":
+        current_pos = (current_pos[0], current_pos[1] - 1)
+
+    if current_char in affected_box_positions:
+        return True
+
+    if current_char != "@":
+        affected_box_positions.append(current_pos)
+
+    pushed_positions = []
+    if current_char == "@":
+        pushed_positions.append(direction)
+    elif direction == (0, 1):
+        pushed_positions.append((0, 2))
+    elif direction == (0, -1):
+        pushed_positions.append(direction)
+    else:
+        pushed_positions.append(direction)
+        pushed_positions.append((direction[0], 1))
+
+    for pushed in pushed_positions:
+        pushed_pos = (current_pos[0] + pushed[0], current_pos[1] + pushed[1])
+        pushed_char = data[pushed_pos[0]][pushed_pos[1]]
+        if pushed_char == "#":
+            return False
+        elif pushed_char == "[" or pushed_char == "]":
+            success = get_affected_boxes_if_can_move(data, pushed_pos, affected_box_positions, direction)
+            if not success:
+                return False
+
+    return True
+
+
+def move(data: list[list[str]], current_pos: tuple[int, int],
+         current_order: str, movement_dict: dict[str, tuple[int, int]]) -> tuple[int, int]:
+    assert data[current_pos[0]][current_pos[1]] == "@"
+
+    direction = movement_dict[current_order]
+    can_move = True
+    steps = 0
+    affected_box_positions = []
+    success = get_affected_boxes_if_can_move(data, current_pos, affected_box_positions, direction)
+    if not success:
+        return current_pos
+
+    data[current_pos[0]][current_pos[1]] = "."
+    for box_pos in affected_box_positions:
+        data[box_pos[0]][box_pos[1]] = "."
+        data[box_pos[0]][box_pos[1] + 1] = "."
+
+    current_pos = (current_pos[0] + direction[0], current_pos[1] + direction[1])
+    data[current_pos[0]][current_pos[1]] = "@"
+
+    for box_pos in affected_box_positions:
+        data[box_pos[0] + direction[0]][box_pos[1] + direction[1]] = "["
+        data[box_pos[0] + direction[0]][box_pos[1] + direction[1] + 1] = "]"
+
+    return current_pos
+
+def calculate_gps_data(data: list[list[str]]):
+    result = 0
+    max_cols = len(data[0])
+    for row_pos, row in enumerate(data):
+        for col_pos, char in enumerate(row):
+            if char == "[":
+                result += row_pos * 100 + col_pos
+    return result
+
+movement_dirs = { "<": (0, -1), "v": (1, 0), "^": (-1, 0), ">": (0, 1) }
+map_data = []
+movement_data = ""
+
+with open("input") as f:
+    reading_movement = False
+    for line in f:
+        line = line.strip()
+        if reading_movement:
+            movement_data += line
+        else:
+            if line == "":
+                reading_movement = True
+            else:
+                new_line = []
+                map_data.append(new_line)
+                for char in line:
+                    if char == ".":
+                        new_line.append(".")
+                        new_line.append(".")
+                    elif char == "#":
+                        new_line.append("#")
+                        new_line.append("#")
+                    elif char == "O":
+                        new_line.append("[")
+                        new_line.append("]")
+                    else:
+                        new_line.append(char)
+                        new_line.append(".")
+
+for row_idx, row in enumerate(map_data):
+    for col_idx, char in enumerate(row):
+        if char == "@":
+            robot_row = row_idx
+            robot_col = col_idx
+            break
+    else:
+        continue
+    break
+
+new_pos = (robot_row, robot_col)
+for order in movement_data:
+    new_pos = move(map_data,new_pos, order, movement_dirs)
+
+for line in map_data:
+    print("".join(line))
+
+print(calculate_gps_data(map_data))
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