Add day 9

Author: LiquidFun

.aoc_tiles/tiles/2023/08.png

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/LiquidFun/aoc_tiles
-    rev: 0.3.3
+    rev: 0.3.4
     hooks:
       - id: aoc-tiles
         args: 

.aoc_tiles/tiles/2023/09.png

@@ -0,0 +1,15 @@
+from sys import stdin
+
+lines = stdin.read().strip().split('\n')
+
+first = last = 0
+for line in lines:
+    diff = [int(a) for a in line.split()]
+    sign = 1
+    while any(diff):
+        last += diff[-1]
+        first += diff[0] * sign
+        sign *= -1
+        diff = [b - a for a, b in zip(diff, diff[1:])]
+
+print(first, last, sep='\n')

.pre-commit-config.yaml

@@ -4,7 +4,7 @@
 
 <!-- AOC TILES BEGIN -->
 <h1 align="center">
-  2023 - 16 ⭐
+  2023 - 18 ⭐
 </h1>
 <a href="2023/01/01.rs">
   <img src=".aoc_tiles/tiles/2023/01.png" width="161px">
@@ -27,9 +27,12 @@
 <a href="2023/07/07.py">
   <img src=".aoc_tiles/tiles/2023/07.png" width="161px">
 </a>
-<a href="2023/08/08.rs">
+<a href="2023/08/08.py">
   <img src=".aoc_tiles/tiles/2023/08.png" width="161px">
 </a>
+<a href="2023/09/09.py">
+  <img src=".aoc_tiles/tiles/2023/09.png" width="161px">
+</a>
 <h1 align="center">
   2022 - 50 ⭐
 </h1>