From 5f74630d0742b12a3bd363d1634b877ba61d773b Mon Sep 17 00:00:00 2001
From: Shaun Wang <spxwang@gmail.com>
Date: Wed, 28 Apr 2021 17:27:20 +1200
Subject: [PATCH] Use 'select_nth_unstable' to get median. (#467)
* Use 'select_nth_unstable' to get median.
* fix
* Update comments doc.
---
oracle/src/default_combine_data.rs | 10 +++++-----
traits/src/data_provider.rs | 7 +++----
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/oracle/src/default_combine_data.rs b/oracle/src/default_combine_data.rs
index 4f096cf..d8c3f08 100644
--- a/oracle/src/default_combine_data.rs
+++ b/oracle/src/default_combine_data.rs
@@ -27,13 +27,13 @@ where
let count = values.len() as u32;
let minimum_count = MinimumCount::get();
- if count < minimum_count {
+ if count < minimum_count || count == 0 {
return prev_value;
}
- values.sort_by(|a, b| a.value.cmp(&b.value));
-
- let median_index = count / 2;
- Some(values[median_index as usize].clone())
+ let mid_index = count / 2;
+ // Won't panic as `values` ensured not empty.
+ let (_, value, _) = values.select_nth_unstable_by(mid_index as usize, |a, b| a.value.cmp(&b.value));
+ Some(value.clone())
}
}
diff --git a/traits/src/data_provider.rs b/traits/src/data_provider.rs
index 4b3483d..650d398 100644
--- a/traits/src/data_provider.rs
+++ b/traits/src/data_provider.rs
@@ -30,10 +30,9 @@ pub fn median<T: Ord + Clone>(mut items: Vec<T>) -> Option<T> {
let mid_index = items.len() / 2;
- items.sort();
-
- // Won't panic as guarded items not empty case.
- Some(items[mid_index as usize].clone())
+ // Won't panic as `items` ensured not empty.
+ let (_, item, _) = items.select_nth_unstable(mid_index);
+ Some(item.clone())
}
#[macro_export]
--
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