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| author | Mazdak Farrokhzad <twingoow@gmail.com> | 2019-04-05 12:46:48 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-04-05 12:46:48 +0200 |
| commit | a3122e12d8bcc2701c26cc3d38b35a818c0d87a6 (patch) | |
| tree | ab833c135f321e6bb2c8524da818b9b61248f05f | |
| parent | a11083e3c6a8eb0610a752dcf8d1af1ce5ca6dee (diff) | |
| parent | 5b8bfe047123bad63ead0370c165cd9307a07caa (diff) | |
| download | rust-a3122e12d8bcc2701c26cc3d38b35a818c0d87a6.tar.gz rust-a3122e12d8bcc2701c26cc3d38b35a818c0d87a6.zip | |
Rollup merge of #59665 - ssomers:hashset_revisited, r=KodrAus
improve worst-case performance of HashSet.is_subset One more simple optimization opportunity for HashSet that was applied in BTreeSet in #59186 (and wasn't in #57043). Already covered by the existing unit test. r? @KodrAus
| -rw-r--r-- | src/libstd/collections/hash/set.rs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs index 89d5b2ff30f..b9fcc2365fa 100644 --- a/src/libstd/collections/hash/set.rs +++ b/src/libstd/collections/hash/set.rs @@ -627,7 +627,11 @@ impl<T, S> HashSet<T, S> /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn is_subset(&self, other: &HashSet<T, S>) -> bool { - self.iter().all(|v| other.contains(v)) + if self.len() <= other.len() { + self.iter().all(|v| other.contains(v)) + } else { + false + } } /// Returns `true` if the set is a superset of another, |