From b5c262097ad6662c1a1975b0008677742c25b3ef Mon Sep 17 00:00:00 2001
From: augustin64 <me.git@augustin64.fr>
Date: Tue, 12 Dec 2023 09:49:16 +0100
Subject: [PATCH] Add 2023 day 12 ':]

---
 2023/day12.py | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100755 2023/day12.py

diff --git a/2023/day12.py b/2023/day12.py
new file mode 100755
index 0000000..d8743cc
--- /dev/null
+++ b/2023/day12.py
@@ -0,0 +1,148 @@
+#!/usr/bin/python3
+"""
+Jour 12 du défi Advent Of Code pour l'année 2023
+"""
+import os
+from functools import cache, wraps
+from time import time
+
+def read_sample():
+    """récupère les entrées depuis le fichier texte correspondant"""
+    filename = os.path.join(os.path.dirname(__file__ ), "inputs", "day12.txt")
+    with open(filename, 'r') as f:
+        sample = f.read().split('\n')
+    sample = [ i for i in sample if i != '' ]
+    return sample
+
+
+def parse_sample(sample):
+    springs = []
+    counts = []
+    for i in range(len(sample)):
+        springs.append(sample[i].split(" ")[0])
+        counts.append([int(i) for i in sample[i].split(" ")[1].split(",")])
+    return springs, counts
+
+
+def timing(f):
+    @wraps(f)
+    def wrap(*args, **kw):
+        ts = time()
+        result = f(*args, **kw)
+        te = time()
+        print('> %s: %2.4f sec' % \
+          (f.__name__, te-ts))
+        return result
+    return wrap
+
+
+def nb_poss(spring, count):
+    def check_new_elem(elem, size, count):
+        if size > len(count):
+            return False
+        if elem != count[size-1]:
+            return False
+        return True
+
+    @cache
+    def nb_poss_rec(actual_count_size, cur, pos, first):
+        """
+            actual_count_size: already added elements
+            cur: current number of # in the spring pos
+            pos: current position in the spring
+            first: first elem of the upcoming spring
+        """
+        # While loop for first elem
+        if pos < len(spring) and first != '?':
+            if first == '.':
+                if cur > 0:
+                    actual_count_size += 1
+                    if not check_new_elem(cur, actual_count_size, count):
+                        return 0
+                    cur = 0
+            elif first == '#':
+                cur += 1
+            pos += 1
+
+        # Exactly the same loop for the other elems
+        while pos < len(spring) and spring[pos] != '?':
+            if spring[pos] == '.':
+                if cur > 0:
+                    actual_count_size += 1
+                    if not check_new_elem(cur, actual_count_size, count):
+                        return 0
+                    cur = 0
+            elif spring[pos] == '#':
+                cur += 1
+            pos += 1
+
+        # spring ends with # ?
+        if pos == len(spring) and cur > 0:
+            actual_count_size += 1
+            if not check_new_elem(cur, actual_count_size, count):
+                return 0
+
+        # End of spring ?
+        if pos >= len(spring):
+            if len(count) == actual_count_size:
+                return 1
+            return 0
+        
+        # Debugging
+        if spring[pos] != '?':
+            print("weird", spring, count, actual_count_size, pos, spring[pos], len(spring))
+            return
+
+        # Recursive calls
+        if spring[pos] == '?':
+            if cur > 0:
+                if len(count) > actual_count_size:
+                    if cur == count[actual_count_size]:
+                        return nb_poss_rec(actual_count_size, cur, pos, '.') # break the #### with a .
+                    elif cur < count[actual_count_size]:
+                        return nb_poss_rec(actual_count_size, cur, pos, '#') # continue with #
+                    else:
+                        return 0 # not possible
+            return nb_poss_rec(actual_count_size, cur, pos, '.') + nb_poss_rec(actual_count_size, cur, pos, '#')
+
+    return nb_poss_rec(0, 0, 0, spring[0])
+
+
+def unfold(springs, counts):
+    for i in range(len(springs)):
+        springs[i] = '?'.join([springs[i]]*5)
+        counts[i] = counts[i]*5
+
+
+@timing
+def part1(sample):
+    """Partie 1 du défi"""
+    springs, counts = parse_sample(sample)
+    possibilities = []
+    for i in range(len(springs)):
+        possibilities.append(nb_poss(springs[i], counts[i]))
+        
+    return sum(possibilities)
+
+
+@timing
+def part2(sample):
+    """Partie 2 du défi"""
+    springs, counts = parse_sample(sample)
+    unfold(springs, counts)
+    
+    possibilities = []
+    for i in range(len(springs)):
+        possibilities.append(nb_poss(springs[i], counts[i]))
+        
+    return sum(possibilities)
+
+
+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