From 1d4c5f6f81f3cf8635bc622f0558016f3208443d Mon Sep 17 00:00:00 2001
From: setop <setop@zoocoop.com>
Date: Sat, 9 Dec 2023 09:17:26 +0100
Subject: [PATCH] day 9, trivial recursion

---
 d09/part1.py | 11 +++++++++++
 d09/part2.py | 11 +++++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 d09/part1.py
 create mode 100644 d09/part2.py

diff --git a/d09/part1.py b/d09/part1.py
new file mode 100644
index 0000000..358e22c
--- /dev/null
+++ b/d09/part1.py
@@ -0,0 +1,11 @@
+import sys
+
+L = [list(map(int,l.split(' '))) for l in sys.stdin.read().splitlines()]
+
+def extrapolate(L):
+    if all(not a for a in L):
+        return L+[0]
+    M = [b-a for a,b in zip(L,L[1:])]
+    return L+[L[-1]+extrapolate(M)[-1]]
+
+print(sum(extrapolate(l)[-1] for l in L))
diff --git a/d09/part2.py b/d09/part2.py
new file mode 100644
index 0000000..ad8aa8b
--- /dev/null
+++ b/d09/part2.py
@@ -0,0 +1,11 @@
+import sys
+
+L = [list(map(int,l.split(' '))) for l in sys.stdin.read().splitlines()]
+
+def extrapolate(L):
+    if all(not a for a in L):
+        return [0]+L
+    M = [b-a for a,b in zip(L,L[1:])]
+    return [L[0]-extrapolate(M)[0]]+L
+
+print(sum(extrapolate(l)[0] for l in L))