From 01503d10591d8327b08f6ffe04d4ec42b82208ce Mon Sep 17 00:00:00 2001
From: Sebastian Mark <smark@posteo.net>
Date: Sun, 15 Dec 2024 18:08:44 +0100
Subject: [PATCH] add 2024/15.1

---
 2024/15/main.py | 110 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 2024/15/main.py

diff --git a/2024/15/main.py b/2024/15/main.py
new file mode 100644
index 0000000..d37a00c
--- /dev/null
+++ b/2024/15/main.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+# -*- encoding: utf-8; py-indent-offset: 4 -*-
+
+# Author: Sebastian Mark
+# CC-BY-SA (https://creativecommons.org/licenses/by-sa/4.0/deed.de)
+
+# pylint: disable=missing-module-docstring,missing-function-docstring,consider-using-f-string
+
+import re
+import copy
+
+DIRECTION = {
+    "^": (-1, 0),
+    "v": (1, 0),
+    "<": (0, -1),
+    ">": (0, 1),
+}
+
+
+def readinput():
+    with open("input", "r", encoding="utf-8") as file:
+        lines = file.readlines()
+        sep = lines.index("\n")
+
+        warehouse = []
+        for line in lines[:sep]:
+            warehouse.append(list(line.strip()))
+
+        directions = ""
+        for line in lines[sep + 1 :]:
+            directions += line.strip()
+
+    return warehouse, directions
+
+
+def find_robot(warehouse: list) -> tuple:
+    for y, line in enumerate(warehouse):
+        try:
+            x = line.index("@")
+        except ValueError:
+            continue
+
+        return (y, x)
+
+
+def run_robot_run(warehouse: list, robot: tuple, directions: list) -> list:
+    sorted_warehouse = copy.deepcopy(warehouse)
+    roboty, robotx = robot
+
+    for d in directions:
+        dy, dx = DIRECTION[d]
+
+        nxty = roboty + dy
+        nxtx = robotx + dx
+
+        # check for border in front of robot
+        if sorted_warehouse[nxty][nxtx] == "#":
+            continue
+
+        # check stack of boxes
+        boxes = []
+        bxchky, bxchkx = nxty, nxtx
+        while sorted_warehouse[bxchky][bxchkx] == "O":
+            boxes.append((bxchky, bxchkx))
+            bxchky += dy
+            bxchkx += dx
+
+        # check for border after last box
+        if sorted_warehouse[bxchky][bxchkx] == "#":
+            continue
+
+        # move boxes
+        for box in boxes:
+            sorted_warehouse[box[0] + dy][box[1] + dx] = "O"
+
+        # move robot
+        sorted_warehouse[roboty][robotx] = "."
+        sorted_warehouse[nxty][nxtx] = "@"
+        roboty, robotx = nxty, nxtx
+
+    return sorted_warehouse
+
+
+def calc_gps_sum(warehouse: list) -> int:
+    gps_sum = 0
+    for y, line in enumerate(warehouse):
+        boxes = re.finditer("O", "".join(line))
+        for box in boxes:
+            gps_sum += 100 * y + box.start()
+
+    return gps_sum
+
+
+def print_area(area: list):
+    for line in area:
+        print("".join(line))
+
+
+def main():
+    warehouse, directions = readinput()
+
+    # part 1
+    robot = find_robot(warehouse)
+    unclutterd_warehouse = run_robot_run(warehouse, robot, directions)
+    gps_sum = calc_gps_sum(unclutterd_warehouse)
+    print("GPS sum: %d" % gps_sum)
+
+
+if __name__ == "__main__":
+    main()