1438 lines
44 KiB
Rust
1438 lines
44 KiB
Rust
// This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
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// to TreeMap
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use core::borrow::Borrow;
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use core::cmp::Ordering::{Equal, Greater, Less};
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use core::cmp::{max, min};
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use core::fmt::{self, Debug};
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use core::iter::{FromIterator, FusedIterator, Peekable};
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use core::ops::{BitAnd, BitOr, BitXor, RangeBounds, Sub};
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use super::Recover;
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use crate::collections::btree_map::{self, BTreeMap, Keys};
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// FIXME(conventions): implement bounded iterators
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/// A set based on a B-Tree.
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///
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/// See [`BTreeMap`]'s documentation for a detailed discussion of this collection's performance
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/// benefits and drawbacks.
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///
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/// It is a logic error for an item to be modified in such a way that the item's ordering relative
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/// to any other item, as determined by the [`Ord`] trait, changes while it is in the set. This is
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/// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code.
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///
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/// [`BTreeMap`]: struct.BTreeMap.html
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/// [`Ord`]: ../../std/cmp/trait.Ord.html
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/// [`Cell`]: ../../std/cell/struct.Cell.html
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/// [`RefCell`]: ../../std/cell/struct.RefCell.html
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BTreeSet;
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///
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/// // Type inference lets us omit an explicit type signature (which
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/// // would be `BTreeSet<&str>` in this example).
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/// let mut books = BTreeSet::new();
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///
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/// // Add some books.
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/// books.insert("A Dance With Dragons");
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/// books.insert("To Kill a Mockingbird");
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/// books.insert("The Odyssey");
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/// books.insert("The Great Gatsby");
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///
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/// // Check for a specific one.
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/// if !books.contains("The Winds of Winter") {
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/// println!("We have {} books, but The Winds of Winter ain't one.",
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/// books.len());
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/// }
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///
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/// // Remove a book.
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/// books.remove("The Odyssey");
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///
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/// // Iterate over everything.
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/// for book in &books {
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/// println!("{}", book);
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/// }
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/// ```
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#[derive(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct BTreeSet<T> {
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map: BTreeMap<T, ()>,
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}
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/// An iterator over the items of a `BTreeSet`.
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///
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/// This `struct` is created by the [`iter`] method on [`BTreeSet`].
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/// See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`iter`]: struct.BTreeSet.html#method.iter
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Iter<'a, T: 'a> {
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iter: Keys<'a, T, ()>,
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}
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#[stable(feature = "collection_debug", since = "1.17.0")]
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impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("Iter").field(&self.iter.clone()).finish()
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}
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}
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/// An owning iterator over the items of a `BTreeSet`.
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///
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/// This `struct` is created by the [`into_iter`] method on [`BTreeSet`][`BTreeSet`]
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/// (provided by the `IntoIterator` trait). See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`into_iter`]: struct.BTreeSet.html#method.into_iter
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#[stable(feature = "rust1", since = "1.0.0")]
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#[derive(Debug)]
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pub struct IntoIter<T> {
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iter: btree_map::IntoIter<T, ()>,
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}
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/// An iterator over a sub-range of items in a `BTreeSet`.
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///
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/// This `struct` is created by the [`range`] method on [`BTreeSet`].
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/// See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`range`]: struct.BTreeSet.html#method.range
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#[derive(Debug)]
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#[stable(feature = "btree_range", since = "1.17.0")]
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pub struct Range<'a, T: 'a> {
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iter: btree_map::Range<'a, T, ()>,
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}
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/// Core of SymmetricDifference and Union.
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/// More efficient than btree.map.MergeIter,
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/// and crucially for SymmetricDifference, nexts() reports on both sides.
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#[derive(Clone)]
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struct MergeIterInner<I>
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where
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I: Iterator,
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I::Item: Copy,
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{
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a: I,
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b: I,
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peeked: Option<MergeIterPeeked<I>>,
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}
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#[derive(Copy, Clone, Debug)]
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enum MergeIterPeeked<I: Iterator> {
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A(I::Item),
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B(I::Item),
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}
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impl<I> MergeIterInner<I>
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where
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I: ExactSizeIterator + FusedIterator,
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I::Item: Copy + Ord,
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{
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fn new(a: I, b: I) -> Self {
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MergeIterInner { a, b, peeked: None }
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}
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fn nexts(&mut self) -> (Option<I::Item>, Option<I::Item>) {
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let mut a_next = match self.peeked {
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Some(MergeIterPeeked::A(next)) => Some(next),
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_ => self.a.next(),
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};
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let mut b_next = match self.peeked {
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Some(MergeIterPeeked::B(next)) => Some(next),
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_ => self.b.next(),
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};
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let ord = match (a_next, b_next) {
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(None, None) => Equal,
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(_, None) => Less,
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(None, _) => Greater,
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(Some(a1), Some(b1)) => a1.cmp(&b1),
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};
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self.peeked = match ord {
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Less => b_next.take().map(MergeIterPeeked::B),
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Equal => None,
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Greater => a_next.take().map(MergeIterPeeked::A),
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};
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(a_next, b_next)
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}
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fn lens(&self) -> (usize, usize) {
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match self.peeked {
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Some(MergeIterPeeked::A(_)) => (1 + self.a.len(), self.b.len()),
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Some(MergeIterPeeked::B(_)) => (self.a.len(), 1 + self.b.len()),
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_ => (self.a.len(), self.b.len()),
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}
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}
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}
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impl<I> Debug for MergeIterInner<I>
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where
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I: Iterator + Debug,
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I::Item: Copy + Debug,
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("MergeIterInner").field(&self.a).field(&self.b).finish()
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}
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}
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/// A lazy iterator producing elements in the difference of `BTreeSet`s.
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///
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/// This `struct` is created by the [`difference`] method on [`BTreeSet`].
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/// See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`difference`]: struct.BTreeSet.html#method.difference
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Difference<'a, T: 'a> {
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inner: DifferenceInner<'a, T>,
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}
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#[derive(Debug)]
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enum DifferenceInner<'a, T: 'a> {
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Stitch {
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// iterate all of `self` and some of `other`, spotting matches along the way
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self_iter: Iter<'a, T>,
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other_iter: Peekable<Iter<'a, T>>,
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},
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Search {
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// iterate `self`, look up in `other`
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self_iter: Iter<'a, T>,
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other_set: &'a BTreeSet<T>,
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},
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Iterate(Iter<'a, T>), // simply produce all values in `self`
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}
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#[stable(feature = "collection_debug", since = "1.17.0")]
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impl<T: fmt::Debug> fmt::Debug for Difference<'_, T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("Difference").field(&self.inner).finish()
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}
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}
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/// A lazy iterator producing elements in the symmetric difference of `BTreeSet`s.
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///
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/// This `struct` is created by the [`symmetric_difference`] method on
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/// [`BTreeSet`]. See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`symmetric_difference`]: struct.BTreeSet.html#method.symmetric_difference
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct SymmetricDifference<'a, T: 'a>(MergeIterInner<Iter<'a, T>>);
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#[stable(feature = "collection_debug", since = "1.17.0")]
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impl<T: fmt::Debug> fmt::Debug for SymmetricDifference<'_, T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("SymmetricDifference").field(&self.0).finish()
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}
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}
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/// A lazy iterator producing elements in the intersection of `BTreeSet`s.
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///
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/// This `struct` is created by the [`intersection`] method on [`BTreeSet`].
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/// See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`intersection`]: struct.BTreeSet.html#method.intersection
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Intersection<'a, T: 'a> {
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inner: IntersectionInner<'a, T>,
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}
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#[derive(Debug)]
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enum IntersectionInner<'a, T: 'a> {
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Stitch {
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// iterate similarly sized sets jointly, spotting matches along the way
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a: Iter<'a, T>,
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b: Iter<'a, T>,
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},
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Search {
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// iterate a small set, look up in the large set
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small_iter: Iter<'a, T>,
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large_set: &'a BTreeSet<T>,
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},
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Answer(Option<&'a T>), // return a specific value or emptiness
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}
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#[stable(feature = "collection_debug", since = "1.17.0")]
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impl<T: fmt::Debug> fmt::Debug for Intersection<'_, T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("Intersection").field(&self.inner).finish()
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}
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}
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/// A lazy iterator producing elements in the union of `BTreeSet`s.
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///
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/// This `struct` is created by the [`union`] method on [`BTreeSet`].
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/// See its documentation for more.
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///
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/// [`BTreeSet`]: struct.BTreeSet.html
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/// [`union`]: struct.BTreeSet.html#method.union
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Union<'a, T: 'a>(MergeIterInner<Iter<'a, T>>);
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#[stable(feature = "collection_debug", since = "1.17.0")]
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impl<T: fmt::Debug> fmt::Debug for Union<'_, T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_tuple("Union").field(&self.0).finish()
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}
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}
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// This constant is used by functions that compare two sets.
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// It estimates the relative size at which searching performs better
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// than iterating, based on the benchmarks in
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// https://github.com/ssomers/rust_bench_btreeset_intersection;
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// It's used to divide rather than multiply sizes, to rule out overflow,
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// and it's a power of two to make that division cheap.
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const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16;
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impl<T: Ord> BTreeSet<T> {
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/// Makes a new `BTreeSet` with a reasonable choice of B.
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///
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/// # Examples
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///
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/// ```
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/// # #![allow(unused_mut)]
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/// use std::collections::BTreeSet;
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///
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/// let mut set: BTreeSet<i32> = BTreeSet::new();
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> BTreeSet<T> {
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BTreeSet { map: BTreeMap::new() }
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}
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/// Constructs a double-ended iterator over a sub-range of elements in the set.
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/// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will
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/// yield elements from min (inclusive) to max (exclusive).
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/// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example
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/// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive
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/// range from 4 to 10.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BTreeSet;
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/// use std::ops::Bound::Included;
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///
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/// let mut set = BTreeSet::new();
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/// set.insert(3);
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/// set.insert(5);
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/// set.insert(8);
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/// for &elem in set.range((Included(&4), Included(&8))) {
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/// println!("{}", elem);
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/// }
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/// assert_eq!(Some(&5), set.range(4..).next());
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/// ```
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#[stable(feature = "btree_range", since = "1.17.0")]
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pub fn range<K: ?Sized, R>(&self, range: R) -> Range<'_, T>
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where
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K: Ord,
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T: Borrow<K>,
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R: RangeBounds<K>,
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{
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Range { iter: self.map.range(range) }
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}
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/// Visits the values representing the difference,
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/// i.e., the values that are in `self` but not in `other`,
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/// in ascending order.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BTreeSet;
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///
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/// let mut a = BTreeSet::new();
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/// a.insert(1);
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/// a.insert(2);
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///
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/// let mut b = BTreeSet::new();
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/// b.insert(2);
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/// b.insert(3);
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///
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/// let diff: Vec<_> = a.difference(&b).cloned().collect();
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/// assert_eq!(diff, [1]);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> {
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let (self_min, self_max) =
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if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) {
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(self_min, self_max)
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} else {
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return Difference { inner: DifferenceInner::Iterate(self.iter()) };
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};
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let (other_min, other_max) =
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if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) {
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(other_min, other_max)
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} else {
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return Difference { inner: DifferenceInner::Iterate(self.iter()) };
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};
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Difference {
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inner: match (self_min.cmp(other_max), self_max.cmp(other_min)) {
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(Greater, _) | (_, Less) => DifferenceInner::Iterate(self.iter()),
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(Equal, _) => {
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let mut self_iter = self.iter();
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self_iter.next();
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DifferenceInner::Iterate(self_iter)
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}
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(_, Equal) => {
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let mut self_iter = self.iter();
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self_iter.next_back();
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DifferenceInner::Iterate(self_iter)
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}
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_ if self.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => {
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DifferenceInner::Search { self_iter: self.iter(), other_set: other }
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}
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_ => DifferenceInner::Stitch {
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self_iter: self.iter(),
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other_iter: other.iter().peekable(),
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},
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},
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}
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}
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/// Visits the values representing the symmetric difference,
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/// i.e., the values that are in `self` or in `other` but not in both,
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/// in ascending order.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BTreeSet;
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///
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/// let mut a = BTreeSet::new();
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/// a.insert(1);
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/// a.insert(2);
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///
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/// let mut b = BTreeSet::new();
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/// b.insert(2);
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/// b.insert(3);
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///
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/// let sym_diff: Vec<_> = a.symmetric_difference(&b).cloned().collect();
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/// assert_eq!(sym_diff, [1, 3]);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn symmetric_difference<'a>(
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&'a self,
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other: &'a BTreeSet<T>,
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) -> SymmetricDifference<'a, T> {
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SymmetricDifference(MergeIterInner::new(self.iter(), other.iter()))
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}
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/// Visits the values representing the intersection,
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/// i.e., the values that are both in `self` and `other`,
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/// in ascending order.
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///
|
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/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
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///
|
|
/// let mut a = BTreeSet::new();
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/// a.insert(1);
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/// a.insert(2);
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///
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/// let mut b = BTreeSet::new();
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/// b.insert(2);
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/// b.insert(3);
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///
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/// let intersection: Vec<_> = a.intersection(&b).cloned().collect();
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/// assert_eq!(intersection, [2]);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>) -> Intersection<'a, T> {
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let (self_min, self_max) =
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if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) {
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(self_min, self_max)
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} else {
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return Intersection { inner: IntersectionInner::Answer(None) };
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};
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let (other_min, other_max) =
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if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) {
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(other_min, other_max)
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} else {
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return Intersection { inner: IntersectionInner::Answer(None) };
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};
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Intersection {
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inner: match (self_min.cmp(other_max), self_max.cmp(other_min)) {
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(Greater, _) | (_, Less) => IntersectionInner::Answer(None),
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(Equal, _) => IntersectionInner::Answer(Some(self_min)),
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(_, Equal) => IntersectionInner::Answer(Some(self_max)),
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_ if self.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => {
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IntersectionInner::Search { small_iter: self.iter(), large_set: other }
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}
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_ if other.len() <= self.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => {
|
|
IntersectionInner::Search { small_iter: other.iter(), large_set: self }
|
|
}
|
|
_ => IntersectionInner::Stitch { a: self.iter(), b: other.iter() },
|
|
},
|
|
}
|
|
}
|
|
|
|
/// Visits the values representing the union,
|
|
/// i.e., all the values in `self` or `other`, without duplicates,
|
|
/// in ascending order.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut a = BTreeSet::new();
|
|
/// a.insert(1);
|
|
///
|
|
/// let mut b = BTreeSet::new();
|
|
/// b.insert(2);
|
|
///
|
|
/// let union: Vec<_> = a.union(&b).cloned().collect();
|
|
/// assert_eq!(union, [1, 2]);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> Union<'a, T> {
|
|
Union(MergeIterInner::new(self.iter(), other.iter()))
|
|
}
|
|
|
|
/// Clears the set, removing all values.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut v = BTreeSet::new();
|
|
/// v.insert(1);
|
|
/// v.clear();
|
|
/// assert!(v.is_empty());
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn clear(&mut self) {
|
|
self.map.clear()
|
|
}
|
|
|
|
/// Returns `true` if the set contains a value.
|
|
///
|
|
/// The value may be any borrowed form of the set's value type,
|
|
/// but the ordering on the borrowed form *must* match the
|
|
/// ordering on the value type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
|
|
/// assert_eq!(set.contains(&1), true);
|
|
/// assert_eq!(set.contains(&4), false);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool
|
|
where
|
|
T: Borrow<Q>,
|
|
Q: Ord,
|
|
{
|
|
self.map.contains_key(value)
|
|
}
|
|
|
|
/// Returns a reference to the value in the set, if any, that is equal to the given value.
|
|
///
|
|
/// The value may be any borrowed form of the set's value type,
|
|
/// but the ordering on the borrowed form *must* match the
|
|
/// ordering on the value type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
|
|
/// assert_eq!(set.get(&2), Some(&2));
|
|
/// assert_eq!(set.get(&4), None);
|
|
/// ```
|
|
#[stable(feature = "set_recovery", since = "1.9.0")]
|
|
pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T>
|
|
where
|
|
T: Borrow<Q>,
|
|
Q: Ord,
|
|
{
|
|
Recover::get(&self.map, value)
|
|
}
|
|
|
|
/// Returns `true` if `self` has no elements in common with `other`.
|
|
/// This is equivalent to checking for an empty intersection.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let a: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
|
|
/// let mut b = BTreeSet::new();
|
|
///
|
|
/// assert_eq!(a.is_disjoint(&b), true);
|
|
/// b.insert(4);
|
|
/// assert_eq!(a.is_disjoint(&b), true);
|
|
/// b.insert(1);
|
|
/// assert_eq!(a.is_disjoint(&b), false);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool {
|
|
self.intersection(other).next().is_none()
|
|
}
|
|
|
|
/// Returns `true` if the set is a subset of another,
|
|
/// i.e., `other` contains at least all the values in `self`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let sup: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// assert_eq!(set.is_subset(&sup), true);
|
|
/// set.insert(2);
|
|
/// assert_eq!(set.is_subset(&sup), true);
|
|
/// set.insert(4);
|
|
/// assert_eq!(set.is_subset(&sup), false);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_subset(&self, other: &BTreeSet<T>) -> bool {
|
|
// Same result as self.difference(other).next().is_none()
|
|
// but the code below is faster (hugely in some cases).
|
|
if self.len() > other.len() {
|
|
return false;
|
|
}
|
|
let (self_min, self_max) =
|
|
if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) {
|
|
(self_min, self_max)
|
|
} else {
|
|
return true; // self is empty
|
|
};
|
|
let (other_min, other_max) =
|
|
if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) {
|
|
(other_min, other_max)
|
|
} else {
|
|
return false; // other is empty
|
|
};
|
|
let mut self_iter = self.iter();
|
|
match self_min.cmp(other_min) {
|
|
Less => return false,
|
|
Equal => {
|
|
self_iter.next();
|
|
}
|
|
Greater => (),
|
|
}
|
|
match self_max.cmp(other_max) {
|
|
Greater => return false,
|
|
Equal => {
|
|
self_iter.next_back();
|
|
}
|
|
Less => (),
|
|
}
|
|
if self_iter.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF {
|
|
for next in self_iter {
|
|
if !other.contains(next) {
|
|
return false;
|
|
}
|
|
}
|
|
} else {
|
|
let mut other_iter = other.iter();
|
|
other_iter.next();
|
|
other_iter.next_back();
|
|
let mut self_next = self_iter.next();
|
|
while let Some(self1) = self_next {
|
|
match other_iter.next().map_or(Less, |other1| self1.cmp(other1)) {
|
|
Less => return false,
|
|
Equal => self_next = self_iter.next(),
|
|
Greater => (),
|
|
}
|
|
}
|
|
}
|
|
true
|
|
}
|
|
|
|
/// Returns `true` if the set is a superset of another,
|
|
/// i.e., `self` contains at least all the values in `other`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let sub: BTreeSet<_> = [1, 2].iter().cloned().collect();
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// assert_eq!(set.is_superset(&sub), false);
|
|
///
|
|
/// set.insert(0);
|
|
/// set.insert(1);
|
|
/// assert_eq!(set.is_superset(&sub), false);
|
|
///
|
|
/// set.insert(2);
|
|
/// assert_eq!(set.is_superset(&sub), true);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_superset(&self, other: &BTreeSet<T>) -> bool {
|
|
other.is_subset(self)
|
|
}
|
|
|
|
/// Returns a reference to the first value in the set, if any.
|
|
/// This value is always the minimum of all values in the set.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// #![feature(map_first_last)]
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut map = BTreeSet::new();
|
|
/// assert_eq!(map.first(), None);
|
|
/// map.insert(1);
|
|
/// assert_eq!(map.first(), Some(&1));
|
|
/// map.insert(2);
|
|
/// assert_eq!(map.first(), Some(&1));
|
|
/// ```
|
|
#[unstable(feature = "map_first_last", issue = "62924")]
|
|
pub fn first(&self) -> Option<&T> {
|
|
self.map.first_key_value().map(|(k, _)| k)
|
|
}
|
|
|
|
/// Returns a reference to the last value in the set, if any.
|
|
/// This value is always the maximum of all values in the set.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// #![feature(map_first_last)]
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut map = BTreeSet::new();
|
|
/// assert_eq!(map.first(), None);
|
|
/// map.insert(1);
|
|
/// assert_eq!(map.last(), Some(&1));
|
|
/// map.insert(2);
|
|
/// assert_eq!(map.last(), Some(&2));
|
|
/// ```
|
|
#[unstable(feature = "map_first_last", issue = "62924")]
|
|
pub fn last(&self) -> Option<&T> {
|
|
self.map.last_key_value().map(|(k, _)| k)
|
|
}
|
|
|
|
/// Removes the first value from the set and returns it, if any.
|
|
/// The first value is always the minimum value in the set.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_first_last)]
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// set.insert(1);
|
|
/// while let Some(n) = set.pop_first() {
|
|
/// assert_eq!(n, 1);
|
|
/// }
|
|
/// assert!(set.is_empty());
|
|
/// ```
|
|
#[unstable(feature = "map_first_last", issue = "62924")]
|
|
pub fn pop_first(&mut self) -> Option<T> {
|
|
self.map.first_entry().map(|entry| entry.remove_entry().0)
|
|
}
|
|
|
|
/// Removes the last value from the set and returns it, if any.
|
|
/// The last value is always the maximum value in the set.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(map_first_last)]
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// set.insert(1);
|
|
/// while let Some(n) = set.pop_last() {
|
|
/// assert_eq!(n, 1);
|
|
/// }
|
|
/// assert!(set.is_empty());
|
|
/// ```
|
|
#[unstable(feature = "map_first_last", issue = "62924")]
|
|
pub fn pop_last(&mut self) -> Option<T> {
|
|
self.map.last_entry().map(|entry| entry.remove_entry().0)
|
|
}
|
|
|
|
/// Adds a value to the set.
|
|
///
|
|
/// If the set did not have this value present, `true` is returned.
|
|
///
|
|
/// If the set did have this value present, `false` is returned, and the
|
|
/// entry is not updated. See the [module-level documentation] for more.
|
|
///
|
|
/// [module-level documentation]: index.html#insert-and-complex-keys
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// assert_eq!(set.insert(2), true);
|
|
/// assert_eq!(set.insert(2), false);
|
|
/// assert_eq!(set.len(), 1);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn insert(&mut self, value: T) -> bool {
|
|
self.map.insert(value, ()).is_none()
|
|
}
|
|
|
|
/// Adds a value to the set, replacing the existing value, if any, that is equal to the given
|
|
/// one. Returns the replaced value.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set = BTreeSet::new();
|
|
/// set.insert(Vec::<i32>::new());
|
|
///
|
|
/// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0);
|
|
/// set.replace(Vec::with_capacity(10));
|
|
/// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10);
|
|
/// ```
|
|
#[stable(feature = "set_recovery", since = "1.9.0")]
|
|
pub fn replace(&mut self, value: T) -> Option<T> {
|
|
Recover::replace(&mut self.map, value)
|
|
}
|
|
|
|
/// Removes a value from the set. Returns whether the value was
|
|
/// present in the set.
|
|
///
|
|
/// The value may be any borrowed form of the set's value type,
|
|
/// but the ordering on the borrowed form *must* match the
|
|
/// ordering on the value type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set = BTreeSet::new();
|
|
///
|
|
/// set.insert(2);
|
|
/// assert_eq!(set.remove(&2), true);
|
|
/// assert_eq!(set.remove(&2), false);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
|
|
where
|
|
T: Borrow<Q>,
|
|
Q: Ord,
|
|
{
|
|
self.map.remove(value).is_some()
|
|
}
|
|
|
|
/// Removes and returns the value in the set, if any, that is equal to the given one.
|
|
///
|
|
/// The value may be any borrowed form of the set's value type,
|
|
/// but the ordering on the borrowed form *must* match the
|
|
/// ordering on the value type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
|
|
/// assert_eq!(set.take(&2), Some(2));
|
|
/// assert_eq!(set.take(&2), None);
|
|
/// ```
|
|
#[stable(feature = "set_recovery", since = "1.9.0")]
|
|
pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T>
|
|
where
|
|
T: Borrow<Q>,
|
|
Q: Ord,
|
|
{
|
|
Recover::take(&mut self.map, value)
|
|
}
|
|
|
|
/// Moves all elements from `other` into `Self`, leaving `other` empty.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut a = BTreeSet::new();
|
|
/// a.insert(1);
|
|
/// a.insert(2);
|
|
/// a.insert(3);
|
|
///
|
|
/// let mut b = BTreeSet::new();
|
|
/// b.insert(3);
|
|
/// b.insert(4);
|
|
/// b.insert(5);
|
|
///
|
|
/// a.append(&mut b);
|
|
///
|
|
/// assert_eq!(a.len(), 5);
|
|
/// assert_eq!(b.len(), 0);
|
|
///
|
|
/// assert!(a.contains(&1));
|
|
/// assert!(a.contains(&2));
|
|
/// assert!(a.contains(&3));
|
|
/// assert!(a.contains(&4));
|
|
/// assert!(a.contains(&5));
|
|
/// ```
|
|
#[stable(feature = "btree_append", since = "1.11.0")]
|
|
pub fn append(&mut self, other: &mut Self) {
|
|
self.map.append(&mut other.map);
|
|
}
|
|
|
|
/// Splits the collection into two at the given key. Returns everything after the given key,
|
|
/// including the key.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut a = BTreeSet::new();
|
|
/// a.insert(1);
|
|
/// a.insert(2);
|
|
/// a.insert(3);
|
|
/// a.insert(17);
|
|
/// a.insert(41);
|
|
///
|
|
/// let b = a.split_off(&3);
|
|
///
|
|
/// assert_eq!(a.len(), 2);
|
|
/// assert_eq!(b.len(), 3);
|
|
///
|
|
/// assert!(a.contains(&1));
|
|
/// assert!(a.contains(&2));
|
|
///
|
|
/// assert!(b.contains(&3));
|
|
/// assert!(b.contains(&17));
|
|
/// assert!(b.contains(&41));
|
|
/// ```
|
|
#[stable(feature = "btree_split_off", since = "1.11.0")]
|
|
pub fn split_off<Q: ?Sized + Ord>(&mut self, key: &Q) -> Self
|
|
where
|
|
T: Borrow<Q>,
|
|
{
|
|
BTreeSet { map: self.map.split_off(key) }
|
|
}
|
|
}
|
|
|
|
impl<T> BTreeSet<T> {
|
|
/// Gets an iterator that visits the values in the `BTreeSet` in ascending order.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let set: BTreeSet<usize> = [1, 2, 3].iter().cloned().collect();
|
|
/// let mut set_iter = set.iter();
|
|
/// assert_eq!(set_iter.next(), Some(&1));
|
|
/// assert_eq!(set_iter.next(), Some(&2));
|
|
/// assert_eq!(set_iter.next(), Some(&3));
|
|
/// assert_eq!(set_iter.next(), None);
|
|
/// ```
|
|
///
|
|
/// Values returned by the iterator are returned in ascending order:
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let set: BTreeSet<usize> = [3, 1, 2].iter().cloned().collect();
|
|
/// let mut set_iter = set.iter();
|
|
/// assert_eq!(set_iter.next(), Some(&1));
|
|
/// assert_eq!(set_iter.next(), Some(&2));
|
|
/// assert_eq!(set_iter.next(), Some(&3));
|
|
/// assert_eq!(set_iter.next(), None);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn iter(&self) -> Iter<'_, T> {
|
|
Iter { iter: self.map.keys() }
|
|
}
|
|
|
|
/// Returns the number of elements in the set.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut v = BTreeSet::new();
|
|
/// assert_eq!(v.len(), 0);
|
|
/// v.insert(1);
|
|
/// assert_eq!(v.len(), 1);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn len(&self) -> usize {
|
|
self.map.len()
|
|
}
|
|
|
|
/// Returns `true` if the set contains no elements.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let mut v = BTreeSet::new();
|
|
/// assert!(v.is_empty());
|
|
/// v.insert(1);
|
|
/// assert!(!v.is_empty());
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_empty(&self) -> bool {
|
|
self.len() == 0
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> FromIterator<T> for BTreeSet<T> {
|
|
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> BTreeSet<T> {
|
|
let mut set = BTreeSet::new();
|
|
set.extend(iter);
|
|
set
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> IntoIterator for BTreeSet<T> {
|
|
type Item = T;
|
|
type IntoIter = IntoIter<T>;
|
|
|
|
/// Gets an iterator for moving out the `BTreeSet`'s contents.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let set: BTreeSet<usize> = [1, 2, 3, 4].iter().cloned().collect();
|
|
///
|
|
/// let v: Vec<_> = set.into_iter().collect();
|
|
/// assert_eq!(v, [1, 2, 3, 4]);
|
|
/// ```
|
|
fn into_iter(self) -> IntoIter<T> {
|
|
IntoIter { iter: self.map.into_iter() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> IntoIterator for &'a BTreeSet<T> {
|
|
type Item = &'a T;
|
|
type IntoIter = Iter<'a, T>;
|
|
|
|
fn into_iter(self) -> Iter<'a, T> {
|
|
self.iter()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> Extend<T> for BTreeSet<T> {
|
|
#[inline]
|
|
fn extend<Iter: IntoIterator<Item = T>>(&mut self, iter: Iter) {
|
|
iter.into_iter().for_each(move |elem| {
|
|
self.insert(elem);
|
|
});
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "extend_ref", since = "1.2.0")]
|
|
impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BTreeSet<T> {
|
|
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
|
|
self.extend(iter.into_iter().cloned());
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> Default for BTreeSet<T> {
|
|
/// Makes an empty `BTreeSet<T>` with a reasonable choice of B.
|
|
fn default() -> BTreeSet<T> {
|
|
BTreeSet::new()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord + Clone> Sub<&BTreeSet<T>> for &BTreeSet<T> {
|
|
type Output = BTreeSet<T>;
|
|
|
|
/// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
|
|
/// let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect();
|
|
///
|
|
/// let result = &a - &b;
|
|
/// let result_vec: Vec<_> = result.into_iter().collect();
|
|
/// assert_eq!(result_vec, [1, 2]);
|
|
/// ```
|
|
fn sub(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
|
|
self.difference(rhs).cloned().collect()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord + Clone> BitXor<&BTreeSet<T>> for &BTreeSet<T> {
|
|
type Output = BTreeSet<T>;
|
|
|
|
/// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
|
|
/// let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect();
|
|
///
|
|
/// let result = &a ^ &b;
|
|
/// let result_vec: Vec<_> = result.into_iter().collect();
|
|
/// assert_eq!(result_vec, [1, 4]);
|
|
/// ```
|
|
fn bitxor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
|
|
self.symmetric_difference(rhs).cloned().collect()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord + Clone> BitAnd<&BTreeSet<T>> for &BTreeSet<T> {
|
|
type Output = BTreeSet<T>;
|
|
|
|
/// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
|
|
/// let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect();
|
|
///
|
|
/// let result = &a & &b;
|
|
/// let result_vec: Vec<_> = result.into_iter().collect();
|
|
/// assert_eq!(result_vec, [2, 3]);
|
|
/// ```
|
|
fn bitand(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
|
|
self.intersection(rhs).cloned().collect()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord + Clone> BitOr<&BTreeSet<T>> for &BTreeSet<T> {
|
|
type Output = BTreeSet<T>;
|
|
|
|
/// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::collections::BTreeSet;
|
|
///
|
|
/// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
|
|
/// let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect();
|
|
///
|
|
/// let result = &a | &b;
|
|
/// let result_vec: Vec<_> = result.into_iter().collect();
|
|
/// assert_eq!(result_vec, [1, 2, 3, 4, 5]);
|
|
/// ```
|
|
fn bitor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
|
|
self.union(rhs).cloned().collect()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Debug> Debug for BTreeSet<T> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.debug_set().entries(self.iter()).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Clone for Iter<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
Iter { iter: self.iter.clone() }
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Iterator for Iter<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
self.iter.next()
|
|
}
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.iter.size_hint()
|
|
}
|
|
fn last(mut self) -> Option<&'a T> {
|
|
self.next_back()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
|
|
fn next_back(&mut self) -> Option<&'a T> {
|
|
self.iter.next_back()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> ExactSizeIterator for Iter<'_, T> {
|
|
fn len(&self) -> usize {
|
|
self.iter.len()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T> FusedIterator for Iter<'_, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Iterator for IntoIter<T> {
|
|
type Item = T;
|
|
|
|
fn next(&mut self) -> Option<T> {
|
|
self.iter.next().map(|(k, _)| k)
|
|
}
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
self.iter.size_hint()
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> DoubleEndedIterator for IntoIter<T> {
|
|
fn next_back(&mut self) -> Option<T> {
|
|
self.iter.next_back().map(|(k, _)| k)
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> ExactSizeIterator for IntoIter<T> {
|
|
fn len(&self) -> usize {
|
|
self.iter.len()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T> FusedIterator for IntoIter<T> {}
|
|
|
|
#[stable(feature = "btree_range", since = "1.17.0")]
|
|
impl<T> Clone for Range<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
Range { iter: self.iter.clone() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "btree_range", since = "1.17.0")]
|
|
impl<'a, T> Iterator for Range<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
self.iter.next().map(|(k, _)| k)
|
|
}
|
|
|
|
fn last(mut self) -> Option<&'a T> {
|
|
self.next_back()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "btree_range", since = "1.17.0")]
|
|
impl<'a, T> DoubleEndedIterator for Range<'a, T> {
|
|
fn next_back(&mut self) -> Option<&'a T> {
|
|
self.iter.next_back().map(|(k, _)| k)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T> FusedIterator for Range<'_, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Clone for Difference<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
Difference {
|
|
inner: match &self.inner {
|
|
DifferenceInner::Stitch { self_iter, other_iter } => DifferenceInner::Stitch {
|
|
self_iter: self_iter.clone(),
|
|
other_iter: other_iter.clone(),
|
|
},
|
|
DifferenceInner::Search { self_iter, other_set } => {
|
|
DifferenceInner::Search { self_iter: self_iter.clone(), other_set }
|
|
}
|
|
DifferenceInner::Iterate(iter) => DifferenceInner::Iterate(iter.clone()),
|
|
},
|
|
}
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: Ord> Iterator for Difference<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
match &mut self.inner {
|
|
DifferenceInner::Stitch { self_iter, other_iter } => {
|
|
let mut self_next = self_iter.next()?;
|
|
loop {
|
|
match other_iter.peek().map_or(Less, |other_next| self_next.cmp(other_next)) {
|
|
Less => return Some(self_next),
|
|
Equal => {
|
|
self_next = self_iter.next()?;
|
|
other_iter.next();
|
|
}
|
|
Greater => {
|
|
other_iter.next();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
DifferenceInner::Search { self_iter, other_set } => loop {
|
|
let self_next = self_iter.next()?;
|
|
if !other_set.contains(&self_next) {
|
|
return Some(self_next);
|
|
}
|
|
},
|
|
DifferenceInner::Iterate(iter) => iter.next(),
|
|
}
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let (self_len, other_len) = match &self.inner {
|
|
DifferenceInner::Stitch { self_iter, other_iter } => {
|
|
(self_iter.len(), other_iter.len())
|
|
}
|
|
DifferenceInner::Search { self_iter, other_set } => (self_iter.len(), other_set.len()),
|
|
DifferenceInner::Iterate(iter) => (iter.len(), 0),
|
|
};
|
|
(self_len.saturating_sub(other_len), Some(self_len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T: Ord> FusedIterator for Difference<'_, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Clone for SymmetricDifference<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
SymmetricDifference(self.0.clone())
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
loop {
|
|
let (a_next, b_next) = self.0.nexts();
|
|
if a_next.and(b_next).is_none() {
|
|
return a_next.or(b_next);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let (a_len, b_len) = self.0.lens();
|
|
// No checked_add, because even if a and b refer to the same set,
|
|
// and T is an empty type, the storage overhead of sets limits
|
|
// the number of elements to less than half the range of usize.
|
|
(0, Some(a_len + b_len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T: Ord> FusedIterator for SymmetricDifference<'_, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Clone for Intersection<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
Intersection {
|
|
inner: match &self.inner {
|
|
IntersectionInner::Stitch { a, b } => {
|
|
IntersectionInner::Stitch { a: a.clone(), b: b.clone() }
|
|
}
|
|
IntersectionInner::Search { small_iter, large_set } => {
|
|
IntersectionInner::Search { small_iter: small_iter.clone(), large_set }
|
|
}
|
|
IntersectionInner::Answer(answer) => IntersectionInner::Answer(*answer),
|
|
},
|
|
}
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: Ord> Iterator for Intersection<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
match &mut self.inner {
|
|
IntersectionInner::Stitch { a, b } => {
|
|
let mut a_next = a.next()?;
|
|
let mut b_next = b.next()?;
|
|
loop {
|
|
match a_next.cmp(b_next) {
|
|
Less => a_next = a.next()?,
|
|
Greater => b_next = b.next()?,
|
|
Equal => return Some(a_next),
|
|
}
|
|
}
|
|
}
|
|
IntersectionInner::Search { small_iter, large_set } => loop {
|
|
let small_next = small_iter.next()?;
|
|
if large_set.contains(&small_next) {
|
|
return Some(small_next);
|
|
}
|
|
},
|
|
IntersectionInner::Answer(answer) => answer.take(),
|
|
}
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
match &self.inner {
|
|
IntersectionInner::Stitch { a, b } => (0, Some(min(a.len(), b.len()))),
|
|
IntersectionInner::Search { small_iter, .. } => (0, Some(small_iter.len())),
|
|
IntersectionInner::Answer(None) => (0, Some(0)),
|
|
IntersectionInner::Answer(Some(_)) => (1, Some(1)),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T: Ord> FusedIterator for Intersection<'_, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Clone for Union<'_, T> {
|
|
fn clone(&self) -> Self {
|
|
Union(self.0.clone())
|
|
}
|
|
}
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: Ord> Iterator for Union<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
let (a_next, b_next) = self.0.nexts();
|
|
a_next.or(b_next)
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let (a_len, b_len) = self.0.lens();
|
|
// No checked_add - see SymmetricDifference::size_hint.
|
|
(max(a_len, b_len), Some(a_len + b_len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "fused", since = "1.26.0")]
|
|
impl<T: Ord> FusedIterator for Union<'_, T> {}
|