From 33f5dce9e51753cae76cf95a876d64e5351ccbfb Mon Sep 17 00:00:00 2001
From: Sven Heidemann <sven.heidemann@sh-edraft.de>
Date: Mon, 12 Dec 2022 08:11:45 +0100
Subject: [PATCH] day 12

---
 src/day12.py | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/day12.py

diff --git a/src/day12.py b/src/day12.py
new file mode 100644
index 0000000..5b97072
--- /dev/null
+++ b/src/day12.py
@@ -0,0 +1,80 @@
+import collections
+import string
+from dataclasses import dataclass
+from typing import Union
+
+from cpl_core.console import Console
+from cpl_query.extension import List
+
+from aoc.aoc import get_input
+
+# global vars
+day = 12
+aoc_input = get_input(2022, day)
+aoc_input1 = """Sabqponm
+abcryxxl
+accszExk
+acctuvwj
+abdefghi"""
+
+
+@dataclass
+class Position:
+    x: int = 0
+    y: int = 0
+
+
+def get_position(grid: List[List[str]], char: str) -> Position:
+    y = grid.index_of(grid.where(lambda row: char in row).single())
+    x = grid.element_at(y).index_of(char)
+    return Position(x, y)
+
+
+def get_path(grid: List[List[Union[str, int]]], start: Position, reverse=False):
+    width = grid.first().count()
+    height = grid.count()
+    directions = [(0, 1), (0, -1), (1, 0), (-1, 0)]
+
+    paths = collections.defaultdict(lambda: 10e15)
+    paths[(start.y, start.x)] = 0
+    should_search = [(start.x, start.y, 0)]
+    while len(should_search) > 0:
+        x, y, steps = should_search[0]
+        should_search = should_search[1:]
+        from_height = ord(grid[y][x])
+
+        for (dx, dy) in directions:
+            nx = x + dx
+            ny = y + dy
+            if nx < 0 or nx >= width or ny < 0 or ny >= height:
+                continue
+
+            to_height = ord(grid[ny][nx])
+
+            if not reverse and not from_height - to_height >= -1:
+                continue
+
+            if reverse and not from_height - to_height <= 1:
+                continue
+
+            if paths[(ny, nx)] > steps + 1:
+                paths[(ny, nx)] = steps + 1
+                should_search.append((nx, ny, steps + 1))
+
+    return paths
+
+
+def main():
+    grid = List(str, aoc_input.splitlines()).select(lambda x: List(int, x))
+    Console.write_line(grid)
+    start = get_position(grid, 'S')
+    target = get_position(grid, 'E')
+    grid: List[List[Union[str, int]]] = grid.select(lambda x: x.select(lambda y: 'a' if y == 'S' else 'z' if y == 'E' else y))
+    Console.write_line(get_path(grid, start)[target.y, target.x])
+    Console.write_line(min([dist for ((y, x), dist) in get_path(grid, target, True).items() if grid[y][x] == 'a']))
+
+
+if __name__ == '__main__':
+    Console.write_line(f'Advent of code day {day}')
+    main()
+    Console.write_line()