From 23ff5e1a6cd78601f24e50fbf21406bb8179d2af Mon Sep 17 00:00:00 2001
From: Nguyễn Gia Phong <cnx@loang.net>
Date: Mon, 2 Dec 2024 16:37:54 +0900
Subject: [aoc/2024] Finish day 2

---
 aoc/2024/02/part-one.py |  6 ++++++
 aoc/2024/02/part-two.py | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 aoc/2024/02/part-one.py
 create mode 100644 aoc/2024/02/part-two.py

diff --git a/aoc/2024/02/part-one.py b/aoc/2024/02/part-one.py
new file mode 100644
index 0000000..e0d74db
--- /dev/null
+++ b/aoc/2024/02/part-one.py
@@ -0,0 +1,6 @@
+from sys import stdin
+
+print(sum(all(0 < d < 4 for d in diffs) or all(-4 < d < 0 for d in diffs)
+          for diffs in (tuple(map(int.__sub__, levels, levels[1:]))
+                        for levels in (tuple(map(int, line))
+                                       for line in map(str.split, stdin)))))
diff --git a/aoc/2024/02/part-two.py b/aoc/2024/02/part-two.py
new file mode 100644
index 0000000..ad5f5a6
--- /dev/null
+++ b/aoc/2024/02/part-two.py
@@ -0,0 +1,21 @@
+from collections import Counter
+from itertools import chain, count
+from sys import stdin
+
+
+def safe(levels, dampened=False):
+    head = levels[0 if 0 < levels[1] - levels[0] < 4 else 1] - 1,
+    tail = levels[-1 if 0 < levels[-1] - levels[-2] < 4 else -2] + 1,
+    dampenable = tuple((not dampened and 0 < a - c < 4
+                        and safe(levels[:i]+levels[i+1:], True))
+                       for i, a, b, c in zip(count(),
+                                             chain(levels[1:], tail),
+                                             levels,
+                                             chain(head, levels))
+                       if not (0 < a - b < 4 and 0 < b - c < 4))
+    return not dampenable or any(dampenable)
+
+
+print(sum(safe(levels) or safe(tuple(map(int.__neg__, levels)))
+          for levels in (tuple(map(int, line))
+                         for line in map(str.split, stdin))))
-- 
cgit 1.4.1