From 643ad7fd8d5380706b3617e97df4a3baa5902cea Mon Sep 17 00:00:00 2001
From: Stefan Harmuth <pennywise@drock.de>
Date: Sun, 12 Nov 2023 18:58:28 +0100
Subject: [PATCH] day12

---
 answer_cache.json   | 14 ++++++++
 day12.py            | 81 +++++++++++++++++++++++++++++++++++++++++++++
 inputs/input12      | 34 +++++++++++++++++++
 inputs/input12_test | 16 +++++++++
 4 files changed, 145 insertions(+)
 create mode 100644 day12.py
 create mode 100644 inputs/input12
 create mode 100644 inputs/input12_test

diff --git a/answer_cache.json b/answer_cache.json
index 0752fb5..10307be 100644
--- a/answer_cache.json
+++ b/answer_cache.json
@@ -103,5 +103,19 @@
             "wrong": [],
             "correct": "90,214,15"
         }
+    },
+    "12": {
+        "1": {
+            "wrong": [],
+            "correct": 3494
+        },
+        "2": {
+            "wrong": [
+                8211,
+                2852454,
+                2850000002511
+            ],
+            "correct": 2850000002454
+        }
     }
 }
\ No newline at end of file
diff --git a/day12.py b/day12.py
new file mode 100644
index 0000000..c2a2c76
--- /dev/null
+++ b/day12.py
@@ -0,0 +1,81 @@
+from tools.aoc import AOCDay
+from typing import Any
+
+
+def simulate_generation(state: str, transform: dict, shift: int) -> (str, int):
+    while not state.startswith("....."):
+        state = '.' + state
+        shift += 1
+
+    while not state.endswith('.....'):
+        state += '.'
+
+    new_state = '..'
+    for x in range(len(state) - 5):
+        key = state[x:x+5]
+        if key not in transform:
+            new_state += '.'
+        else:
+            new_state += transform[key]
+
+    while new_state.startswith('.'):
+        new_state = new_state[1:]
+        shift -= 1
+
+    return new_state, shift
+
+
+def get_pot_value(state: str, shift: int) -> int:
+    sum = 0
+    for i, x in enumerate(state):
+        if x == '#':
+            sum += i - shift
+
+    return sum
+
+
+class Day(AOCDay):
+    inputs = [
+        [
+            (325, "input12_test"),
+            (3494, "input12"),
+        ],
+        [
+            (2850000002454, "input12"),
+        ]
+    ]
+
+    def parse_input(self) -> (str, dict):
+        state = self.getInput()[0].split(": ")[1]
+
+        transform = {}
+        for line in self.getInput()[2:]:
+            k, v = line.split(" => ")
+            transform[k] = v
+
+        return state, transform
+
+    def part1(self) -> Any:
+        state, transform = self.parse_input()
+        shift = 0
+        for x in range(20):
+            state, shift = simulate_generation(state, transform, shift)
+
+        return get_pot_value(state, shift)
+
+    def part2(self) -> Any:
+        cache = {}
+        num_gens = 50_000_000_000
+        state, transform = self.parse_input()
+        cache[state] = (0, 0)
+        shift = 0
+        for x in range(1, num_gens + 1):
+            state, shift = simulate_generation(state, transform, shift)
+            if state in cache:
+                return get_pot_value(state, (-num_gens + 11))
+            cache[state] = (x, shift)
+
+
+if __name__ == '__main__':
+    day = Day(2018, 12)
+    day.run(verbose=True)
diff --git a/inputs/input12 b/inputs/input12
new file mode 100644
index 0000000..67d1e34
--- /dev/null
+++ b/inputs/input12
@@ -0,0 +1,34 @@
+initial state: #.#####.#.#.####.####.#.#...#.......##..##.#.#.#.###..#.....#.####..#.#######.#....####.#....##....#
+
+##.## => .
+#.#.. => .
+..... => .
+##..# => #
+###.. => #
+.##.# => .
+..#.. => #
+##.#. => #
+.##.. => .
+#..#. => .
+###.# => #
+.#### => #
+.#.## => .
+#.##. => #
+.###. => #
+##### => .
+..##. => .
+#.#.# => .
+...#. => #
+..### => .
+.#.#. => #
+.#... => #
+##... => #
+.#..# => #
+#.### => #
+#..## => #
+....# => .
+####. => .
+#...# => #
+#.... => .
+...## => .
+..#.# => #
diff --git a/inputs/input12_test b/inputs/input12_test
new file mode 100644
index 0000000..8335d88
--- /dev/null
+++ b/inputs/input12_test
@@ -0,0 +1,16 @@
+initial state: #..#.#..##......###...###
+
+...## => #
+..#.. => #
+.#... => #
+.#.#. => #
+.#.## => #
+.##.. => #
+.#### => #
+#.#.# => #
+#.### => #
+##.#. => #
+##.## => #
+###.. => #
+###.# => #
+####. => #
\ No newline at end of file