day17

1 files changed, 41 insertions, 0 deletions

diff --git a/src/bin/day17.rs b/src/bin/day17.rs
new file mode 100644
index 0000000..1f3d009
--- /dev/null
+++ b/src/bin/day17.rs
@@ -0,0 +1,41 @@
+use itertools::Itertools;
+
+fn main() {
+    let input = advent::read_numbers(17);
+    println!("17a: {}", container_fittings(&input, 150));
+    println!("17b: {}", minimum_containers(&input, 150));
+}
+
+fn container_fittings(input: &[u16], target: u16) -> usize {
+    input.iter()
+         .powerset()
+         .filter(|containers| containers.iter().copied().sum::<u16>() == target)
+         .count()
+}
+
+fn minimum_containers(input: &[u16], target: u16) -> usize {
+    let min_count = input.iter()
+                         .powerset()
+                         .filter(|containers| containers.iter().copied().sum::<u16>() == target)
+                         .map(|containers| containers.len())
+                         .min()
+                         .unwrap();
+
+    input.iter()
+         .powerset()
+         .filter(|containers| containers.len() == min_count)
+         .filter(|containers| containers.iter().copied().sum::<u16>() == target)
+         .count()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = [20, 15, 10, 5, 5];
+        assert_eq!(container_fittings(&input, 25), 4);
+        assert_eq!(minimum_containers(&input, 25), 3);
+    }
+}