1 files changed, 59 insertions, 0 deletions
diff --git a/2024/22/python.py b/2024/22/python.py
new file mode 100755
index 0000000..98d8898
--- /dev/null
+++ b/2024/22/python.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+
+from collections import Counter, deque
+from fileinput import input
+from itertools import islice
+
+lines = [int(line.strip()) for line in input()]
+
+
+def secrets(secret):
+    x = secret
+    while True:
+        yield x
+        x ^= x << 6
+        x &= 0xFFFFFF
+        x ^= x >> 5
+        x &= 0xFFFFFF
+        x ^= x << 11
+        x &= 0xFFFFFF
+
+
+def prices(it):
+    for s in it:
+        yield s % 10
+
+
+def diff(it):
+    prev = next(it)
+    for curr in it:
+        yield curr, curr - prev
+        prev = curr
+
+
+def to_seqs(it, n=4):
+    head = map(lambda x: x[1], islice(it, n - 1))
+    q = deque(head, maxlen=n)
+    for price, diff in it:
+        q.append(diff)
+        yield price, tuple(q)
+
+
+def seq_sells(it):
+    sells = {}
+    for price, diff in it:
+        if diff in sells:
+            continue
+        sells[diff] = price
+    return sells
+
+
+best_seqs = Counter()
+for x in lines:
+    best_seqs += seq_sells(to_seqs(islice(diff(prices(secrets(x))), 2000)))
+
+silver = sum(next(islice(secrets(x), 2000, None)) for x in lines)
+gold = best_seqs.most_common(1)[0][1]
+
+print("silver:", silver)
+print("gold:", gold)