1 files changed, 7 insertions, 0 deletions

diff --git a/rust/etl/src/lib.rs b/rust/etl/src/lib.rs
new file mode 100644
index 0000000..dd0752c
--- /dev/null
+++ b/rust/etl/src/lib.rs
@@ -0,0 +1,7 @@
+use std::collections::BTreeMap;
+
+pub fn transform(h: &BTreeMap<i32, Vec<char>>) -> BTreeMap<char, i32> {
+    h.iter()
+        .flat_map(|(k, v)| v.iter().map(move |x| (x.to_ascii_lowercase(), *k)))
+        .collect()
+}