From ac0b8697bb6d6291fc95cfa387d4c807d67b3ce7 Mon Sep 17 00:00:00 2001
From: Thibaud <thibaud.gasser@gmx.com>
Date: Fri, 5 Jun 2026 11:05:24 +0200
Subject: [PATCH] 2015 day 15

---
 adventofcode/2015/day15/day15.py | 105 +++++++++++++++++++++++++++++++
 adventofcode/helper.py           |   7 ++-
 2 files changed, 109 insertions(+), 3 deletions(-)
 create mode 100644 adventofcode/2015/day15/day15.py

diff --git a/adventofcode/2015/day15/day15.py b/adventofcode/2015/day15/day15.py
new file mode 100644
index 0000000..dd708d7
--- /dev/null
+++ b/adventofcode/2015/day15/day15.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+import fileinput
+import re
+from functools import reduce
+from itertools import combinations
+from operator import mul
+
+
+def parse_ingredients(inp):
+    ingredients = []
+    for line in inp:
+        ingredients.append(tuple(map(int, re.findall(r"(-?\d+)", line))))
+    return ingredients
+
+
+def generate_combinations():
+    "Generate combinations of length 4 that sum to 100"
+    for x, y, z in combinations(range(1, 100), 3):
+        a = x
+        b = y - x
+        c = z - y
+        d = 100 - z
+        yield (a, b, c, d)
+
+
+def example(ingredients):
+    # for example input, two ingredients such that
+    # a + b = 100 with a and b >= 0
+    max_score = 0
+    for a in range(0, 101):
+        b = 100 - a
+        # ignore last property (calories)
+        qty_a = [x * a for x in ingredients[0][:-1]]
+        qty_b = [x * b for x in ingredients[1][:-1]]
+        props = [x + y if x + y > 0 else 0 for x, y in zip(qty_a, qty_b)]
+        score = reduce(mul, props)
+        max_score = max(score, max_score)
+    return max_score
+
+
+def example_part2(ingredients):
+    max_score = 0
+    for a in range(0, 101):
+        b = 100 - a
+        qty_a = [x * a for x in ingredients[0]]
+        qty_b = [x * b for x in ingredients[1]]
+        # check calories == 500
+        if qty_a[-1] + qty_b[-1] != 500:
+            continue
+        props = [x + y if x + y > 0 else 0 for x, y in zip(qty_a, qty_b)]
+        score = reduce(mul, props[:-1])
+        max_score = max(score, max_score)
+    return max_score
+
+
+def part1(ingredients):
+    max_score = 0
+    for a, b, c, d in generate_combinations():
+        qty_a = [x * a for x in ingredients[0][:-1]]
+        qty_b = [x * b for x in ingredients[1][:-1]]
+        qty_c = [x * c for x in ingredients[2][:-1]]
+        qty_d = [x * d for x in ingredients[3][:-1]]
+        props = [
+            x + y + z + w if x + y + z + w > 0 else 0
+            for x, y, z, w in zip(qty_a, qty_b, qty_c, qty_d)
+        ]
+        score = reduce(mul, props)
+        max_score = max(score, max_score)
+    return max_score
+
+
+def part2(ingredients):
+    max_score = 0
+    for a, b, c, d in generate_combinations():
+        qty_a = [x * a for x in ingredients[0]]
+        qty_b = [x * b for x in ingredients[1]]
+        qty_c = [x * c for x in ingredients[2]]
+        qty_d = [x * d for x in ingredients[3]]
+        props = [
+            x + y + z + w if x + y + z + w > 0 else 0
+            for x, y, z, w in zip(qty_a, qty_b, qty_c, qty_d)
+        ]
+        # check calories == 500
+        calories = sum(x[-1] for x in [qty_a, qty_b, qty_c, qty_d])
+        if calories != 500:
+            continue
+        score = reduce(mul, props[:-1])
+        max_score = max(score, max_score)
+    return max_score
+
+
+def main(inp):
+    ingredients = parse_ingredients(inp)
+    if len(ingredients) == 2:  # example
+        print("Part 1: ", example(ingredients))
+        print("Part 2: ", example_part2(ingredients))
+    else:
+        print("Part 1: ", part1(ingredients))
+        print("Part 2: ", part2(ingredients))
+
+
+if __name__ == "__main__":
+    with fileinput.input() as f:
+        lines = [x.rstrip() for x in fileinput.input()]
+    main(lines)
diff --git a/adventofcode/helper.py b/adventofcode/helper.py
index 3ee0060..7f3dcec 100644
--- a/adventofcode/helper.py
+++ b/adventofcode/helper.py
@@ -14,12 +14,13 @@ import fileinput
 
 
 def main(inp):
-    for l in inp:
-        print(l)
+    for line in inp:
+        print(line)
 
 
 if __name__ == '__main__':
-    lines = [x.rstrip() for x in fileinput.input()]
+    with fileinput.input() as f:
+        lines = [x.rstrip() for x in fileinput.input()]
     main(lines)
 """