From 2d9b37be557727585e2b4ba4d8a31deec22b9366 Mon Sep 17 00:00:00 2001
From: felixm <mail@felixm.de>
Date: Sat, 30 Dec 2023 12:10:52 -0500
Subject: [PATCH] Solve day 18.

---
 README.md | 21 ++++++++++------
 d18.py    | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 7 deletions(-)
 create mode 100644 d18.py

diff --git a/README.md b/README.md
index 4aa0f94..1dbd103 100644
--- a/README.md
+++ b/README.md
@@ -1,19 +1,26 @@
 # Times
 
 - Day  1: 7:52 ... so slow brah :/ top 100 required 2:05...
-- Day  2: 22:30 ... I mistyped the first and second was just bad top 100 would have been 6:16 (doable?)
+- Day  2: 22:30 ... I mistyped the first and second was just bad top 100 would
+  have been 6:16 (doable?)
 - Day  3: 13:08 actually decent but top 100 required 5:24
 - Day  4: 7:08 but top 100 required 3:33 still okay
 - Day  5: 11:56 but 7:58 for top 100... getting better?
 - Day  6: 3:50 but 2:25 for leaderboard :D
 - Day  7: 27:55 and 14:47 for leaderboard; okay, I would say
-- Day  8: 61:00 and 10:00 for leaderboard; I need template code for searching coordinate systems
+- Day  8: 61:00 and 10:00 for leaderboard; I need template code for searching
+  coordinate systems
 - Day  9: 58:00 and 7:32 for leaderboard; I need code for 2D stuff
 - Day 10: 25:20 and 12:17 for leaderboard; okay, okay
 - Day 11: 45:00 and 18:00 for leaderboard; arg, it was doable man
-- Day 12: 39:45 and 9:46 for leaderboard; the people are ready for their searches :D
-- Day 13: 44:00 and 12:56 for leaderboard; these people are just good, seriously
+- Day 12: 39:45 and 9:46 for leaderboard; the people are ready for their
+  searches :D
+- Day 13: 44:00 and 12:56 for leaderboard; these people are just good,
+  seriously
 - Day 14: 35:00 and 14:54; I just have to get that much quicker... 2D code!
-- Day 15: 150:00 and 27:00; I didn't use Manhatten dist initially, lot's of debugging
-- Day 16: 52:00 and 64:00; ARE YOU SAYING I WOULD HAVE MADE THE LEADERBOARD?!?!?!?!?!?!?!
-- Day 17:
+- Day 15: 150:00 and 27:00; I didn't use Manhattan dist initially, lot's of
+  debugging
+- Day 16: 52:00 and 64:00; ARE YOU SAYING I WOULD HAVE MADE THE
+  LEADERBOARD?!?!?!?!?!?!?!
+- Day 17: Second one was fun with having to detect the repetition.
+- Day 18: 12:00 and 32:00; really straightforward and of course way too slow.
diff --git a/d18.py b/d18.py
new file mode 100644
index 0000000..3429712
--- /dev/null
+++ b/d18.py
@@ -0,0 +1,71 @@
+from lib import *
+
+EXAMPLE = """2,2,2
+1,2,2
+3,2,2
+2,1,2
+2,3,2
+2,2,1
+2,2,3
+2,2,4
+2,2,6
+1,2,5
+3,2,5
+2,1,5
+2,3,5
+"""
+
+
+def solve(input: Input, second=False):
+    cubes = set([tuple(map(int, l.split(",")))for l in input.text.splitlines()])
+    res = len(cubes) * 6
+
+    if second:
+        min_x = min([c[0] for c in cubes]) - 1
+        max_x = max([c[0] for c in cubes]) + 1
+        min_y = min([c[1] for c in cubes]) - 1
+        max_y = max([c[1] for c in cubes]) + 1
+        min_z = min([c[2] for c in cubes]) - 1
+        max_z = max([c[2] for c in cubes]) + 1
+        surrounded = set([(x, y, z)
+                          for x in range(min_x, max_x + 1)
+                          for y in range(min_y, max_y + 1)
+                          for z in range(min_z, max_z + 1)])
+        surrounded -= cubes
+        vs = [(min_x, min_y, min_z)]
+        while vs:
+            (x, y, z) = vs.pop()
+            for dx, dy, dz in [(1, 0, 0), (-1, 0, 0), (0, 1, 0), (0, -1, 0), (0, 0, 1), (0, 0, -1)]:
+                t  = x + dx, y + dy, z + dz
+                if t in surrounded:
+                    surrounded.remove(t)
+                    vs.append(t)
+        for x, y, z in list(surrounded):
+            for dx, dy, dz in [(1, 0, 0), (-1, 0, 0), (0, 1, 0), (0, -1, 0), (0, 0, 1), (0, 0, -1)]:
+                nc = x + dx, y + dy, z + dz
+                if nc in cubes:
+                    res -= 1
+
+    for x, y, z in list(cubes):
+        for dx, dy, dz in [(1, 0, 0), (-1, 0, 0), (0, 1, 0), (0, -1, 0), (0, 0, 1), (0, 0, -1)]:
+            nc = x + dx, y + dy, z + dz
+            if nc in cubes:
+                res -= 1
+    return res
+
+def main():
+    DAY_INPUT = "i18.txt"
+
+    print("Example  1:", solve(Input(EXAMPLE)))
+    print("Solution 1:", solve(Input(DAY_INPUT)))
+    # 10:30........
+
+    print("Example  2:", solve(Input(EXAMPLE), True))
+    print("Solution 2:", solve(Input(DAY_INPUT), True))
+    assert solve(Input(DAY_INPUT), True) == 2064
+    # 30:00
+
+    return
+
+if __name__ == "__main__":
+    main()