From aa2c1012c9116829bf8a31818beeec5e3929d3b0 Mon Sep 17 00:00:00 2001
From: augustin64 <me.git@augustin64.fr>
Date: Sat, 9 Dec 2023 10:12:35 +0100
Subject: [PATCH] Add 2023 day 09

---
 2023/day09.py | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100755 2023/day09.py

diff --git a/2023/day09.py b/2023/day09.py
new file mode 100755
index 0000000..7c27a42
--- /dev/null
+++ b/2023/day09.py
@@ -0,0 +1,55 @@
+#!/usr/bin/python3
+"""
+Jour 09 du défi Advent Of Code pour l'année 2023
+"""
+
+def read_sample():
+    """récupère les entrées depuis le fichier texte correspondant"""
+    with open('inputs/day09.txt', 'r') as f:
+        sample = f.read().split('\n')
+    sample = [ [int(j) for j in i.split()] for i in sample if i != '' ]
+    return sample
+
+
+def differences(seq):
+    return [seq[i+1]-seq[i] for i in range(len(seq)-1)]
+
+def null_list(seq):
+    return False not in [i==0 for i in seq]
+
+def extrapolate(seq, rev=False):
+    if rev:
+        seq = list(reversed(seq))
+        
+    seqs = [seq]
+    while not null_list(seqs[-1]):
+        seqs.append(differences(seqs[-1]))
+
+    seqs[-1].append(0)
+    for i in range(len(seqs)-1):
+        seq = seqs[len(seqs)-2-i]
+        prev = seqs[len(seqs)-i-1]
+        seqs[len(seqs)-2-i].append(seq[-1]+prev[-1])
+
+    return seqs
+
+        
+
+
+def part1(sample):
+    """Partie 1 du défi"""
+    return sum([extrapolate(seq, rev=False)[0][-1] for seq in sample])
+
+def part2(sample):
+    """Partie 2 du défi"""
+    return sum([extrapolate(seq, rev=True)[0][-1] for seq in sample])
+
+
+def main():
+    """Fonction principale"""
+    sample = read_sample()
+    print(f"part1: {part1(sample)}")
+    print(f"part2: {part2(sample)}")
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file