diff --git a/zcash_history/examples/long.rs b/zcash_history/examples/long.rs
index a2b2b9077..bcd8d39f0 100644
--- a/zcash_history/examples/long.rs
+++ b/zcash_history/examples/long.rs
@@ -3,7 +3,7 @@ use zcash_history::{Entry, EntryLink, NodeData, Tree};
 #[path = "lib/shared.rs"]
 mod share;
 
-fn draft(into: &mut Vec<(u32, Entry)>, vec: &Vec<NodeData>, peak_pos: usize, h: u32) {
+fn draft(into: &mut Vec<(u32, Entry)>, vec: &[NodeData], peak_pos: usize, h: u32) {
     let node_data = vec[peak_pos - 1].clone();
     let peak: Entry = match h {
         0 => node_data.into(),
@@ -19,7 +19,7 @@ fn draft(into: &mut Vec<(u32, Entry)>, vec: &Vec<NodeData>, peak_pos: usize, h:
     into.push(((peak_pos - 1) as u32, peak));
 }
 
-fn prepare_tree(vec: &Vec<NodeData>) -> Tree {
+fn prepare_tree(vec: &[NodeData]) -> Tree {
     assert!(!vec.is_empty());
 
     // integer log2 of (vec.len()+1), -1