From f4b23383135d02b108832ace26c19e666ba6fa89 Mon Sep 17 00:00:00 2001
From: timeshifter <timeshifter@sumatrae>
Date: Tue, 23 Jun 2026 21:48:01 +0200
Subject: [PATCH] add day 15

---
 day15/Cargo.lock  |   7 +++
 day15/Cargo.toml  |   6 ++
 day15/input.txt   |   4 ++
 day15/src/main.rs | 151 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 168 insertions(+)
 create mode 100644 day15/Cargo.lock
 create mode 100644 day15/Cargo.toml
 create mode 100644 day15/input.txt
 create mode 100644 day15/src/main.rs

diff --git a/day15/Cargo.lock b/day15/Cargo.lock
new file mode 100644
index 0000000..a6ac8d2
--- /dev/null
+++ b/day15/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day15"
+version = "0.1.0"
diff --git a/day15/Cargo.toml b/day15/Cargo.toml
new file mode 100644
index 0000000..c787d54
--- /dev/null
+++ b/day15/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day15"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/day15/input.txt b/day15/input.txt
new file mode 100644
index 0000000..6f33d01
--- /dev/null
+++ b/day15/input.txt
@@ -0,0 +1,4 @@
+Sprinkles: capacity 2, durability 0, flavor -2, texture 0, calories 3
+Butterscotch: capacity 0, durability 5, flavor -3, texture 0, calories 3
+Chocolate: capacity 0, durability 0, flavor 5, texture -1, calories 8
+Candy: capacity 0, durability -1, flavor 0, texture 5, calories 8
diff --git a/day15/src/main.rs b/day15/src/main.rs
new file mode 100644
index 0000000..6930e8d
--- /dev/null
+++ b/day15/src/main.rs
@@ -0,0 +1,151 @@
+fn main() {
+    let data: Vec<_> = std::fs::read_to_string("input.txt")
+        .unwrap()
+        .lines()
+        .map(Ingredient::parse)
+        .collect();
+
+    part1(&data);
+    part2(&data);
+}
+
+fn part2(data: &[Ingredient]) {
+    let mut best = 0;
+    for a in 0..=100 {
+        for b in 0..=(100 - a) {
+            for c in 0..=(100 - b) {
+                'middle: for d in 0..=(100 - c) {
+                    if a + b + c + d != 100 {
+                        continue;
+                    }
+                    let cap: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.capacity))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let dur: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.durability))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let flavor: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.flavor))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let texture: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.texture))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let cal: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.calories))
+                        .map(|(l, r)| l * r)
+                        .sum();
+
+                    for item in [cap, dur, flavor, texture, cal] {
+                        if item <= 0 {
+                            continue 'middle;
+                        }
+                    }
+                    if cal != 500 {
+                        continue;
+                    }
+
+                    let product = cap * dur * flavor * texture;
+                    if product > best {
+                        best = product;
+                    }
+                }
+            }
+        }
+    }
+    println!("{best}")
+}
+
+fn part1(data: &[Ingredient]) {
+    let mut best = 0;
+    for a in 0..=100 {
+        for b in 0..=(100 - a) {
+            for c in 0..=(100 - b) {
+                'middle: for d in 0..=(100 - c) {
+                    if a + b + c + d != 100 {
+                        continue;
+                    }
+                    let cap: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.capacity))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let dur: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.durability))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let flavor: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.flavor))
+                        .map(|(l, r)| l * r)
+                        .sum();
+                    let texture: i64 = [a, b, c, d]
+                        .into_iter()
+                        .zip(data.iter().map(|i| i.texture))
+                        .map(|(l, r)| l * r)
+                        .sum();
+
+                    for item in [cap, dur, flavor, texture] {
+                        if item <= 0 {
+                            continue 'middle;
+                        }
+                    }
+
+                    let product = cap * dur * flavor * texture;
+                    if product > best {
+                        best = product;
+                    }
+                }
+            }
+        }
+    }
+    println!("{best}")
+}
+
+#[derive(Debug)]
+struct Ingredient {
+    pub capacity: i64,
+    pub durability: i64,
+    pub flavor: i64,
+    pub texture: i64,
+    pub calories: i64,
+}
+
+fn helper(s: &str) -> i64 {
+    s.chars()
+        .take_while(|c| *c != ',')
+        .collect::<String>()
+        .parse()
+        .unwrap()
+}
+
+impl Ingredient {
+    fn parse(s: &str) -> Self {
+        let mut iter = s.split_whitespace();
+
+        let capacity = helper(iter.nth(2).unwrap());
+        let durability = helper(iter.nth(1).unwrap());
+        let flavor = helper(iter.nth(1).unwrap());
+        let texture = helper(iter.nth(1).unwrap());
+        let calories = helper(iter.nth(1).unwrap());
+
+        Self {
+            capacity,
+            durability,
+            flavor,
+            texture,
+            calories,
+        }
+    }
+}
+
+// https://adventofcode.com/2015/day/15