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// This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
// to TreeMap
use core::borrow::Borrow;
use core::cmp::Ordering::{self, Less, Greater, Equal};
use core::cmp::max;
use core::fmt::{self, Debug};
use core::iter::{Peekable, FromIterator, FusedIterator};
use core::ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds};
use crate::collections::btree_map::{self, BTreeMap, Keys};
use super::Recover;
// FIXME(conventions): implement bounded iterators
/// A set based on a B-Tree.
///
/// See [`BTreeMap`]'s documentation for a detailed discussion of this collection's performance
/// benefits and drawbacks.
///
/// It is a logic error for an item to be modified in such a way that the item's ordering relative
/// to any other item, as determined by the [`Ord`] trait, changes while it is in the set. This is
/// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code.
///
/// [`BTreeMap`]: struct.BTreeMap.html
/// [`Ord`]: ../../std/cmp/trait.Ord.html
/// [`Cell`]: ../../std/cell/struct.Cell.html
/// [`RefCell`]: ../../std/cell/struct.RefCell.html
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// // Type inference lets us omit an explicit type signature (which
/// // would be `BTreeSet<&str>` in this example).
/// let mut books = BTreeSet::new();
///
/// // Add some books.
/// books.insert("A Dance With Dragons");
/// books.insert("To Kill a Mockingbird");
/// books.insert("The Odyssey");
/// books.insert("The Great Gatsby");
///
/// // Check for a specific one.
/// if !books.contains("The Winds of Winter") {
/// println!("We have {} books, but The Winds of Winter ain't one.",
/// books.len());
/// }
///
/// // Remove a book.
/// books.remove("The Odyssey");
///
/// // Iterate over everything.
/// for book in &books {
/// println!("{}", book);
/// }
/// ```
#[derive(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct BTreeSet<T> {
map: BTreeMap<T, ()>,
}
/// An iterator over the items of a `BTreeSet`.
///
/// This `struct` is created by the [`iter`] method on [`BTreeSet`].
/// See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`iter`]: struct.BTreeSet.html#method.iter
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Iter<'a, T: 'a> {
iter: Keys<'a, T, ()>,
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("Iter")
.field(&self.iter.clone())
.finish()
}
}
/// An owning iterator over the items of a `BTreeSet`.
///
/// This `struct` is created by the [`into_iter`] method on [`BTreeSet`][`BTreeSet`]
/// (provided by the `IntoIterator` trait). See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`into_iter`]: struct.BTreeSet.html#method.into_iter
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(Debug)]
pub struct IntoIter<T> {
iter: btree_map::IntoIter<T, ()>,
}
/// An iterator over a sub-range of items in a `BTreeSet`.
///
/// This `struct` is created by the [`range`] method on [`BTreeSet`].
/// See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`range`]: struct.BTreeSet.html#method.range
#[derive(Debug)]
#[stable(feature = "btree_range", since = "1.17.0")]
pub struct Range<'a, T: 'a> {
iter: btree_map::Range<'a, T, ()>,
}
/// A lazy iterator producing elements in the difference of `BTreeSet`s.
///
/// This `struct` is created by the [`difference`] method on [`BTreeSet`].
/// See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`difference`]: struct.BTreeSet.html#method.difference
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Difference<'a, T: 'a> {
inner: DifferenceInner<'a, T>,
}
enum DifferenceInner<'a, T: 'a> {
Stitch {
self_iter: Iter<'a, T>,
other_iter: Peekable<Iter<'a, T>>,
},
Search {
self_iter: Iter<'a, T>,
other_set: &'a BTreeSet<T>,
},
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug> fmt::Debug for Difference<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.inner {
DifferenceInner::Stitch {
self_iter,
other_iter,
} => f
.debug_tuple("Difference")
.field(&self_iter)
.field(&other_iter)
.finish(),
DifferenceInner::Search {
self_iter,
other_set: _,
} => f.debug_tuple("Difference").field(&self_iter).finish(),
}
}
}
/// A lazy iterator producing elements in the symmetric difference of `BTreeSet`s.
///
/// This `struct` is created by the [`symmetric_difference`] method on
/// [`BTreeSet`]. See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`symmetric_difference`]: struct.BTreeSet.html#method.symmetric_difference
#[stable(feature = "rust1", since = "1.0.0")]
pub struct SymmetricDifference<'a, T: 'a> {
a: Peekable<Iter<'a, T>>,
b: Peekable<Iter<'a, T>>,
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug> fmt::Debug for SymmetricDifference<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("SymmetricDifference")
.field(&self.a)
.field(&self.b)
.finish()
}
}
/// A lazy iterator producing elements in the intersection of `BTreeSet`s.
///
/// This `struct` is created by the [`intersection`] method on [`BTreeSet`].
/// See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`intersection`]: struct.BTreeSet.html#method.intersection
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Intersection<'a, T: 'a> {
inner: IntersectionInner<'a, T>,
}
enum IntersectionInner<'a, T: 'a> {
Stitch {
small_iter: Iter<'a, T>, // for size_hint, should be the smaller of the sets
other_iter: Iter<'a, T>,
},
Search {
small_iter: Iter<'a, T>,
large_set: &'a BTreeSet<T>,
},
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug> fmt::Debug for Intersection<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.inner {
IntersectionInner::Stitch {
small_iter,
other_iter,
} => f
.debug_tuple("Intersection")
.field(&small_iter)
.field(&other_iter)
.finish(),
IntersectionInner::Search {
small_iter,
large_set: _,
} => f.debug_tuple("Intersection").field(&small_iter).finish(),
}
}
}
/// A lazy iterator producing elements in the union of `BTreeSet`s.
///
/// This `struct` is created by the [`union`] method on [`BTreeSet`].
/// See its documentation for more.
///
/// [`BTreeSet`]: struct.BTreeSet.html
/// [`union`]: struct.BTreeSet.html#method.union
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Union<'a, T: 'a> {
a: Peekable<Iter<'a, T>>,
b: Peekable<Iter<'a, T>>,
}
#[stable(feature = "collection_debug", since = "1.17.0")]
impl<T: fmt::Debug> fmt::Debug for Union<'_, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("Union")
.field(&self.a)
.field(&self.b)
.finish()
}
}
// This constant is used by functions that compare two sets.
// It estimates the relative size at which searching performs better
// than iterating, based on the benchmarks in
// https://github.com/ssomers/rust_bench_btreeset_intersection;
// It's used to divide rather than multiply sizes, to rule out overflow,
// and it's a power of two to make that division cheap.
const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16;
impl<T: Ord> BTreeSet<T> {
/// Makes a new `BTreeSet` with a reasonable choice of B.
///
/// # Examples
///
/// ```
/// # #![allow(unused_mut)]
/// use std::collections::BTreeSet;
///
/// let mut set: BTreeSet<i32> = BTreeSet::new();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn new() -> BTreeSet<T> {
BTreeSet { map: BTreeMap::new() }
}
/// Constructs a double-ended iterator over a sub-range of elements in the set.
/// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will
/// yield elements from min (inclusive) to max (exclusive).
/// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example
/// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive
/// range from 4 to 10.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
/// use std::ops::Bound::Included;
///
/// let mut set = BTreeSet::new();
/// set.insert(3);
/// set.insert(5);
/// set.insert(8);
/// for &elem in set.range((Included(&4), Included(&8))) {
/// println!("{}", elem);
/// }
/// assert_eq!(Some(&5), set.range(4..).next());
/// ```
#[stable(feature = "btree_range", since = "1.17.0")]
pub fn range<K: ?Sized, R>(&self, range: R) -> Range<'_, T>
where K: Ord, T: Borrow<K>, R: RangeBounds<K>
{
Range { iter: self.map.range(range) }
}
/// Visits the values representing the difference,
/// i.e., the values that are in `self` but not in `other`,
/// in ascending order.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut a = BTreeSet::new();
/// a.insert(1);
/// a.insert(2);
///
/// let mut b = BTreeSet::new();
/// b.insert(2);
/// b.insert(3);
///
/// let diff: Vec<_> = a.difference(&b).cloned().collect();
/// assert_eq!(diff, [1]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> {
if self.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF {
// Self is bigger than or not much smaller than other set.
// Iterate both sets jointly, spotting matches along the way.
Difference {
inner: DifferenceInner::Stitch {
self_iter: self.iter(),
other_iter: other.iter().peekable(),
},
}
} else {
// Self is much smaller than other set, or both sets are empty.
// Iterate the small set, searching for matches in the large set.
Difference {
inner: DifferenceInner::Search {
self_iter: self.iter(),
other_set: other,
},
}
}
}
/// Visits the values representing the symmetric difference,
/// i.e., the values that are in `self` or in `other` but not in both,
/// in ascending order.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut a = BTreeSet::new();
/// a.insert(1);
/// a.insert(2);
///
/// let mut b = BTreeSet::new();
/// b.insert(2);
/// b.insert(3);
///
/// let sym_diff: Vec<_> = a.symmetric_difference(&b).cloned().collect();
/// assert_eq!(sym_diff, [1, 3]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn symmetric_difference<'a>(&'a self,
other: &'a BTreeSet<T>)
-> SymmetricDifference<'a, T> {
SymmetricDifference {
a: self.iter().peekable(),
b: other.iter().peekable(),
}
}
/// Visits the values representing the intersection,
/// i.e., the values that are both in `self` and `other`,
/// in ascending order.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut a = BTreeSet::new();
/// a.insert(1);
/// a.insert(2);
///
/// let mut b = BTreeSet::new();
/// b.insert(2);
/// b.insert(3);
///
/// let intersection: Vec<_> = a.intersection(&b).cloned().collect();
/// assert_eq!(intersection, [2]);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>) -> Intersection<'a, T> {
let (small, other) = if self.len() <= other.len() {
(self, other)
} else {
(other, self)
};
if small.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF {
// Small set is not much smaller than other set.
// Iterate both sets jointly, spotting matches along the way.
Intersection {
inner: IntersectionInner::Stitch {
small_iter: small.iter(),
other_iter: other.iter(),
},
}
} else {
// Big difference in number of elements, or both sets are empty.
// Iterate the small set, searching for matches in the large set.
Intersection {
inner: IntersectionInner::Search {
small_iter: small.iter(),
large_set: other,
},
}
}
}
/// 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 {
a: self.iter().peekable(),
b: other.iter().peekable(),
}
}
/// 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 3 paths below are faster (in order: hugely, 20%, 5%).
if self.len() > other.len() {
false
} else if self.len() > other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF {
// Self is not much smaller than other set.
// Stolen from TreeMap
let mut x = self.iter();
let mut y = other.iter();
let mut a = x.next();
let mut b = y.next();
while a.is_some() {
if b.is_none() {
return false;
}
let a1 = a.unwrap();
let b1 = b.unwrap();
match b1.cmp(a1) {
Less => (),
Greater => return false,
Equal => a = x.next(),
}
b = y.next();
}
true
} else {
// Big difference in number of elements, or both sets are empty.
// Iterate the small set, searching for matches in the large set.
for next in self {
if !other.contains(next) {
return false;
}
}
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)
}
/// 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> {}
/// Compares `x` and `y`, but return `short` if x is None and `long` if y is None
fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>, short: Ordering, long: Ordering) -> Ordering {
match (x, y) {
(None, _) => short,
(_, None) => long,
(Some(x1), Some(y1)) => x1.cmp(y1),
}
}
#[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,
},
},
}
}
}
#[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| Ord::cmp(self_next, 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);
}
},
}
}
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()),
};
(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 {
a: self.a.clone(),
b: self.b.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 {
match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
Less => return self.a.next(),
Equal => {
self.a.next();
self.b.next();
}
Greater => return self.b.next(),
}
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
(0, Some(self.a.len() + self.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 {
small_iter,
other_iter,
} => IntersectionInner::Stitch {
small_iter: small_iter.clone(),
other_iter: other_iter.clone(),
},
IntersectionInner::Search {
small_iter,
large_set,
} => IntersectionInner::Search {
small_iter: small_iter.clone(),
large_set,
},
},
}
}
}
#[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 {
small_iter,
other_iter,
} => {
let mut small_next = small_iter.next()?;
let mut other_next = other_iter.next()?;
loop {
match Ord::cmp(small_next, other_next) {
Less => small_next = small_iter.next()?,
Greater => other_next = other_iter.next()?,
Equal => return Some(small_next),
}
}
}
IntersectionInner::Search {
small_iter,
large_set,
} => loop {
let small_next = small_iter.next()?;
if large_set.contains(&small_next) {
return Some(small_next);
}
},
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let min_len = match &self.inner {
IntersectionInner::Stitch { small_iter, .. } => small_iter.len(),
IntersectionInner::Search { small_iter, .. } => small_iter.len(),
};
(0, Some(min_len))
}
}
#[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 {
a: self.a.clone(),
b: self.b.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> {
match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
Less => self.a.next(),
Equal => {
self.b.next();
self.a.next()
}
Greater => self.b.next(),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let a_len = self.a.len();
let b_len = self.b.len();
(max(a_len, b_len), Some(a_len + b_len))
}
}
#[stable(feature = "fused", since = "1.26.0")]
impl<T: Ord> FusedIterator for Union<'_, T> {}
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