1 files changed, 22 insertions, 0 deletions

diff --git a/rust/grade-school/src/lib.rs b/rust/grade-school/src/lib.rs
new file mode 100644
index 0000000..266fb1f
--- /dev/null
+++ b/rust/grade-school/src/lib.rs
@@ -0,0 +1,22 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+#[derive(Default)]
+pub struct School(BTreeMap<u32, BTreeSet<String>>);
+
+impl School {
+    pub fn new() -> School {
+        Self::default()
+    }
+
+    pub fn add(&mut self, grade: u32, student: &str) {
+        self.0.entry(grade).or_default().insert(student.to_string());
+    }
+
+    pub fn grades(&self) -> Vec<u32> {
+        self.0.keys().cloned().collect()
+    }
+
+    pub fn grade(&self, grade: u32) -> Option<Vec<String>> {
+        self.0.get(&grade).map(|vs| vs.iter().cloned().collect())
+    }
+}