y2015d24 pretty easy also but had to use itertools instead of my own combinations/permutations impl because of an overflow

y2015/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 [dependencies]
 md5 = "0.7.0"
 utils = { workspace = true }
+itertools = { workspace = true }

y2015/resources/24_input.txt

@@ -0,0 +1,29 @@
+1
+2
+3
+5
+7
+13
+17
+19
+23
+29
+31
+37
+41
+43
+53
+59
+61
+67
+71
+73
+79
+83
+89
+97
+101
+103
+107
+109
+113

y2015/src/bin/d24.rs

@@ -0,0 +1,20 @@
+use std::fs;
+
+use y2015::days::d24;
+
+fn main() {
+    part1();
+    part2();
+}
+
+fn part1() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/24_input.txt")).unwrap();
+    println!("{}", d24::process_part1(&content));
+}
+
+fn part2() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/24_input.txt")).unwrap();
+    println!("{}", d24::process_part2(&content));
+}

y2015/src/days/d24.rs

@@ -0,0 +1,106 @@
+use itertools::Itertools;
+
+#[derive(Clone, Debug, Default)]
+struct Group {
+    packages: Vec<usize>,
+    weight: usize,
+}
+
+impl Group {
+    fn new(packages: Vec<usize>) -> Self {
+        let mut group = Self::default();
+        for package in packages {
+            group.add(package);
+        }
+        group
+    }
+
+    fn add(&mut self, package: usize) {
+        self.packages.push(package);
+        self.weight += package;
+    }
+
+    fn qe(&self) -> usize {
+        self.packages.iter().product()
+    }
+
+    fn len(&self) -> usize {
+        self.packages.len()
+    }
+}
+
+pub fn process_part1(input: &str) -> usize {
+    let packages = input
+        .lines()
+        .map(|line| line.parse::<usize>().unwrap())
+        .collect::<Vec<usize>>();
+    let group_weight = packages.iter().sum::<usize>() / 3;
+    let mut best_group = (usize::MAX, usize::MAX);
+    for k in 1..packages.len() {
+        let combinations = packages.clone().into_iter().combinations(k);
+        for combination in combinations {
+            let group = Group::new(combination.clone());
+            if group.weight == group_weight {
+                if group.len() < best_group.0 {
+                    best_group = (group.len(), group.qe());
+                }
+                if group.len() == best_group.0 && group.qe() < best_group.1 {
+                    best_group = (group.len(), group.qe());
+                }
+            }
+        }
+    }
+    best_group.1
+}
+
+pub fn process_part2(input: &str) -> usize {
+    let packages = input
+        .lines()
+        .map(|line| line.parse::<usize>().unwrap())
+        .collect::<Vec<usize>>();
+    let group_weight = packages.iter().sum::<usize>() / 4;
+    let mut best_group = (usize::MAX, usize::MAX);
+    for k in 1..packages.len() {
+        let combinations = packages.clone().into_iter().combinations(k);
+        for combination in combinations {
+            let group = Group::new(combination.clone());
+            if group.weight == group_weight {
+                if group.len() < best_group.0 {
+                    best_group = (group.len(), group.qe());
+                }
+                if group.len() == best_group.0 && group.qe() < best_group.1 {
+                    best_group = (group.len(), group.qe());
+                }
+            }
+        }
+    }
+    best_group.1
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const INPUT: &str = "1
+2
+3
+4
+5
+7
+8
+9
+10
+11";
+
+    #[test]
+    fn part1() {
+        let result = process_part1(INPUT);
+        assert_eq!(result, 99);
+    }
+
+    #[test]
+    fn part2() {
+        let result = process_part2(INPUT);
+        assert_eq!(result, 44);
+    }
+}

y2015/src/days/mod.rs

@@ -26,3 +26,5 @@ pub mod d21;
 pub mod d22;
 
 pub mod d23;
+
+pub mod d24;