rust/src/libcollections/treemap.rs

1737 lines
52 KiB
Rust

// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! An ordered map and set implemented as self-balancing binary search
//! trees. The only requirement for the types is that the key implements
//! `TotalOrd`.
use std::iter::{Peekable};
use std::cmp::Ordering;
use std::mem::{replace, swap};
use std::ptr;
// This is implemented as an AA tree, which is a simplified variation of
// a red-black tree where red (horizontal) nodes can only be added
// as a right child. The time complexity is the same, and re-balancing
// operations are more frequent but also cheaper.
// Future improvements:
// range search - O(log n) retrieval of an iterator from some key
// (possibly) implement the overloads Python does for sets:
// * intersection: &
// * difference: -
// * symmetric difference: ^
// * union: |
// These would be convenient since the methods work like `each`
#[allow(missing_doc)]
#[deriving(Clone)]
pub struct TreeMap<K, V> {
priv root: Option<~TreeNode<K, V>>,
priv length: uint
}
impl<K: Eq + TotalOrd, V: Eq> Eq for TreeMap<K, V> {
fn eq(&self, other: &TreeMap<K, V>) -> bool {
self.len() == other.len() &&
self.iter().zip(other.iter()).all(|(a, b)| a == b)
}
}
// Lexicographical comparison
fn lt<K: Ord + TotalOrd, V: Ord>(a: &TreeMap<K, V>,
b: &TreeMap<K, V>) -> bool {
// the Zip iterator is as long as the shortest of a and b.
for ((key_a, value_a), (key_b, value_b)) in a.iter().zip(b.iter()) {
if *key_a < *key_b { return true; }
if *key_a > *key_b { return false; }
if *value_a < *value_b { return true; }
if *value_a > *value_b { return false; }
}
a.len() < b.len()
}
impl<K: Ord + TotalOrd, V: Ord> Ord for TreeMap<K, V> {
#[inline]
fn lt(&self, other: &TreeMap<K, V>) -> bool { lt(self, other) }
#[inline]
fn le(&self, other: &TreeMap<K, V>) -> bool { !lt(other, self) }
#[inline]
fn ge(&self, other: &TreeMap<K, V>) -> bool { !lt(self, other) }
#[inline]
fn gt(&self, other: &TreeMap<K, V>) -> bool { lt(other, self) }
}
impl<K: TotalOrd, V> Container for TreeMap<K, V> {
/// Return the number of elements in the map
fn len(&self) -> uint { self.length }
/// Return true if the map contains no elements
fn is_empty(&self) -> bool { self.root.is_none() }
}
impl<K: TotalOrd, V> Mutable for TreeMap<K, V> {
/// Clear the map, removing all key-value pairs.
fn clear(&mut self) {
self.root = None;
self.length = 0
}
}
impl<K: TotalOrd, V> Map<K, V> for TreeMap<K, V> {
/// Return a reference to the value corresponding to the key
fn find<'a>(&'a self, key: &K) -> Option<&'a V> {
let mut current: &'a Option<~TreeNode<K, V>> = &self.root;
loop {
match *current {
Some(ref r) => {
match key.cmp(&r.key) {
Less => current = &r.left,
Greater => current = &r.right,
Equal => return Some(&r.value)
}
}
None => return None
}
}
}
}
impl<K: TotalOrd, V> MutableMap<K, V> for TreeMap<K, V> {
/// Return a mutable reference to the value corresponding to the key
#[inline]
fn find_mut<'a>(&'a mut self, key: &K) -> Option<&'a mut V> {
find_mut(&mut self.root, key)
}
/// Insert a key-value pair from the map. If the key already had a value
/// present in the map, that value is returned. Otherwise None is returned.
fn swap(&mut self, key: K, value: V) -> Option<V> {
let ret = insert(&mut self.root, key, value);
if ret.is_none() { self.length += 1 }
ret
}
/// Removes a key from the map, returning the value at the key if the key
/// was previously in the map.
fn pop(&mut self, key: &K) -> Option<V> {
let ret = remove(&mut self.root, key);
if ret.is_some() { self.length -= 1 }
ret
}
}
impl<K: TotalOrd, V> TreeMap<K, V> {
/// Create an empty TreeMap
pub fn new() -> TreeMap<K, V> { TreeMap{root: None, length: 0} }
/// Get a lazy iterator over the key-value pairs in the map.
/// Requires that it be frozen (immutable).
pub fn iter<'a>(&'a self) -> Entries<'a, K, V> {
Entries {
stack: ~[],
node: deref(&self.root),
remaining_min: self.length,
remaining_max: self.length
}
}
/// Get a lazy reverse iterator over the key-value pairs in the map.
/// Requires that it be frozen (immutable).
pub fn rev_iter<'a>(&'a self) -> RevEntries<'a, K, V> {
RevEntries{iter: self.iter()}
}
/// Get a lazy forward iterator over the key-value pairs in the
/// map, with the values being mutable.
pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, K, V> {
MutEntries {
stack: ~[],
node: mut_deref(&mut self.root),
remaining_min: self.length,
remaining_max: self.length
}
}
/// Get a lazy reverse iterator over the key-value pairs in the
/// map, with the values being mutable.
pub fn mut_rev_iter<'a>(&'a mut self) -> RevMutEntries<'a, K, V> {
RevMutEntries{iter: self.mut_iter()}
}
/// Get a lazy iterator that consumes the treemap.
pub fn move_iter(self) -> MoveEntries<K, V> {
let TreeMap { root: root, length: length } = self;
let stk = match root {
None => ~[],
Some(~tn) => ~[tn]
};
MoveEntries {
stack: stk,
remaining: length
}
}
}
// range iterators.
macro_rules! bound_setup {
// initialiser of the iterator to manipulate
($iter:expr,
// whether we are looking for the lower or upper bound.
$is_lower_bound:expr) => {
{
let mut iter = $iter;
loop {
if !iter.node.is_null() {
let node_k = unsafe {&(*iter.node).key};
match k.cmp(node_k) {
Less => iter.traverse_left(),
Greater => iter.traverse_right(),
Equal => {
if $is_lower_bound {
iter.traverse_complete();
return iter;
} else {
iter.traverse_right()
}
}
}
} else {
iter.traverse_complete();
return iter;
}
}
}
}
}
impl<K: TotalOrd, V> TreeMap<K, V> {
/// Get a lazy iterator that should be initialized using
/// `traverse_left`/`traverse_right`/`traverse_complete`.
fn iter_for_traversal<'a>(&'a self) -> Entries<'a, K, V> {
Entries {
stack: ~[],
node: deref(&self.root),
remaining_min: 0,
remaining_max: self.length
}
}
/// Return a lazy iterator to the first key-value pair whose key is not less than `k`
/// If all keys in map are less than `k` an empty iterator is returned.
pub fn lower_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
bound_setup!(self.iter_for_traversal(), true)
}
/// Return a lazy iterator to the first key-value pair whose key is greater than `k`
/// If all keys in map are not greater than `k` an empty iterator is returned.
pub fn upper_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
bound_setup!(self.iter_for_traversal(), false)
}
/// Get a lazy iterator that should be initialized using
/// `traverse_left`/`traverse_right`/`traverse_complete`.
fn mut_iter_for_traversal<'a>(&'a mut self) -> MutEntries<'a, K, V> {
MutEntries {
stack: ~[],
node: mut_deref(&mut self.root),
remaining_min: 0,
remaining_max: self.length
}
}
/// Return a lazy value iterator to the first key-value pair (with
/// the value being mutable) whose key is not less than `k`.
///
/// If all keys in map are less than `k` an empty iterator is
/// returned.
pub fn mut_lower_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
bound_setup!(self.mut_iter_for_traversal(), true)
}
/// Return a lazy iterator to the first key-value pair (with the
/// value being mutable) whose key is greater than `k`.
///
/// If all keys in map are not greater than `k` an empty iterator
/// is returned.
pub fn mut_upper_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
bound_setup!(self.mut_iter_for_traversal(), false)
}
}
/// Lazy forward iterator over a map
pub struct Entries<'a, K, V> {
priv stack: ~[&'a TreeNode<K, V>],
// See the comment on MutEntries; this is just to allow
// code-sharing (for this immutable-values iterator it *could* very
// well be Option<&'a TreeNode<K,V>>).
priv node: *TreeNode<K, V>,
priv remaining_min: uint,
priv remaining_max: uint
}
/// Lazy backward iterator over a map
pub struct RevEntries<'a, K, V> {
priv iter: Entries<'a, K, V>,
}
/// Lazy forward iterator over a map that allows for the mutation of
/// the values.
pub struct MutEntries<'a, K, V> {
priv stack: ~[&'a mut TreeNode<K, V>],
// Unfortunately, we require some unsafe-ness to get around the
// fact that we would be storing a reference *into* one of the
// nodes in the stack.
//
// As far as the compiler knows, this would let us invalidate the
// reference by assigning a new value to this node's position in
// its parent, which would cause this current one to be
// deallocated so this reference would be invalid. (i.e. the
// compilers complaints are 100% correct.)
//
// However, as far as you humans reading this code know (or are
// about to know, if you haven't read far enough down yet), we are
// only reading from the TreeNode.{left,right} fields. the only
// thing that is ever mutated is the .value field (although any
// actual mutation that happens is done externally, by the
// iterator consumer). So, don't be so concerned, rustc, we've got
// it under control.
//
// (This field can legitimately be null.)
priv node: *mut TreeNode<K, V>,
priv remaining_min: uint,
priv remaining_max: uint
}
/// Lazy backward iterator over a map
pub struct RevMutEntries<'a, K, V> {
priv iter: MutEntries<'a, K, V>,
}
// FIXME #5846 we want to be able to choose between &x and &mut x
// (with many different `x`) below, so we need to optionally pass mut
// as a tt, but the only thing we can do with a `tt` is pass them to
// other macros, so this takes the `& <mutability> <operand>` token
// sequence and forces their evalutation as an expression.
macro_rules! addr { ($e:expr) => { $e }}
// putting an optional mut into type signatures
macro_rules! item { ($i:item) => { $i }}
macro_rules! define_iterator {
($name:ident,
$rev_name:ident,
// the function to go from &m Option<~TreeNode> to *m TreeNode
deref = $deref:ident,
// see comment on `addr!`, this is just an optional `mut`, but
// there's no support for 0-or-1 repeats.
addr_mut = $($addr_mut:tt)*
) => {
// private methods on the forward iterator (item!() for the
// addr_mut in the next_ return value)
item!(impl<'a, K, V> $name<'a, K, V> {
#[inline(always)]
fn next_(&mut self, forward: bool) -> Option<(&'a K, &'a $($addr_mut)* V)> {
while !self.stack.is_empty() || !self.node.is_null() {
if !self.node.is_null() {
let node = unsafe {addr!(& $($addr_mut)* *self.node)};
{
let next_node = if forward {
addr!(& $($addr_mut)* node.left)
} else {
addr!(& $($addr_mut)* node.right)
};
self.node = $deref(next_node);
}
self.stack.push(node);
} else {
let node = self.stack.pop().unwrap();
let next_node = if forward {
addr!(& $($addr_mut)* node.right)
} else {
addr!(& $($addr_mut)* node.left)
};
self.node = $deref(next_node);
self.remaining_max -= 1;
if self.remaining_min > 0 {
self.remaining_min -= 1;
}
return Some((&node.key, addr!(& $($addr_mut)* node.value)));
}
}
None
}
/// traverse_left, traverse_right and traverse_complete are
/// used to initialize Entries/MutEntries
/// pointing to element inside tree structure.
///
/// They should be used in following manner:
/// - create iterator using TreeMap::[mut_]iter_for_traversal
/// - find required node using `traverse_left`/`traverse_right`
/// (current node is `Entries::node` field)
/// - complete initialization with `traverse_complete`
///
/// After this, iteration will start from `self.node`. If
/// `self.node` is None iteration will start from last
/// node from which we traversed left.
#[inline]
fn traverse_left(&mut self) {
let node = unsafe {addr!(& $($addr_mut)* *self.node)};
self.node = $deref(addr!(& $($addr_mut)* node.left));
self.stack.push(node);
}
#[inline]
fn traverse_right(&mut self) {
let node = unsafe {addr!(& $($addr_mut)* *self.node)};
self.node = $deref(addr!(& $($addr_mut)* node.right));
}
#[inline]
fn traverse_complete(&mut self) {
if !self.node.is_null() {
unsafe {
self.stack.push(addr!(& $($addr_mut)* *self.node));
}
self.node = ptr::RawPtr::null();
}
}
})
// the forward Iterator impl.
item!(impl<'a, K, V> Iterator<(&'a K, &'a $($addr_mut)* V)> for $name<'a, K, V> {
/// Advance the iterator to the next node (in order) and return a
/// tuple with a reference to the key and value. If there are no
/// more nodes, return `None`.
fn next(&mut self) -> Option<(&'a K, &'a $($addr_mut)* V)> {
self.next_(true)
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
(self.remaining_min, Some(self.remaining_max))
}
})
// the reverse Iterator impl.
item!(impl<'a, K, V> Iterator<(&'a K, &'a $($addr_mut)* V)> for $rev_name<'a, K, V> {
fn next(&mut self) -> Option<(&'a K, &'a $($addr_mut)* V)> {
self.iter.next_(false)
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
self.iter.size_hint()
}
})
}
} // end of define_iterator
define_iterator! {
Entries,
RevEntries,
deref = deref,
// immutable, so no mut
addr_mut =
}
define_iterator! {
MutEntries,
RevMutEntries,
deref = mut_deref,
addr_mut = mut
}
fn deref<'a, K, V>(node: &'a Option<~TreeNode<K, V>>) -> *TreeNode<K, V> {
match *node {
Some(ref n) => {
let n: &TreeNode<K, V> = *n;
n as *TreeNode<K, V>
}
None => ptr::null()
}
}
fn mut_deref<K, V>(x: &mut Option<~TreeNode<K, V>>) -> *mut TreeNode<K, V> {
match *x {
Some(ref mut n) => {
let n: &mut TreeNode<K, V> = *n;
n as *mut TreeNode<K, V>
}
None => ptr::mut_null()
}
}
/// Lazy forward iterator over a map that consumes the map while iterating
pub struct MoveEntries<K, V> {
priv stack: ~[TreeNode<K, V>],
priv remaining: uint
}
impl<K, V> Iterator<(K, V)> for MoveEntries<K,V> {
#[inline]
fn next(&mut self) -> Option<(K, V)> {
while !self.stack.is_empty() {
let TreeNode {
key: key,
value: value,
left: left,
right: right,
level: level
} = self.stack.pop().unwrap();
match left {
Some(~left) => {
let n = TreeNode {
key: key,
value: value,
left: None,
right: right,
level: level
};
self.stack.push(n);
self.stack.push(left);
}
None => {
match right {
Some(~right) => self.stack.push(right),
None => ()
}
self.remaining -= 1;
return Some((key, value))
}
}
}
None
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
(self.remaining, Some(self.remaining))
}
}
impl<'a, T> Iterator<&'a T> for SetItems<'a, T> {
/// Advance the iterator to the next node (in order). If there are no more nodes, return `None`.
#[inline]
fn next(&mut self) -> Option<&'a T> {
self.iter.next().map(|(value, _)| value)
}
}
impl<'a, T> Iterator<&'a T> for RevSetItems<'a, T> {
/// Advance the iterator to the next node (in order). If there are no more nodes, return `None`.
#[inline]
fn next(&mut self) -> Option<&'a T> {
self.iter.next().map(|(value, _)| value)
}
}
/// A implementation of the `Set` trait on top of the `TreeMap` container. The
/// only requirement is that the type of the elements contained ascribes to the
/// `TotalOrd` trait.
#[deriving(Clone)]
pub struct TreeSet<T> {
priv map: TreeMap<T, ()>
}
impl<T: Eq + TotalOrd> Eq for TreeSet<T> {
#[inline]
fn eq(&self, other: &TreeSet<T>) -> bool { self.map == other.map }
#[inline]
fn ne(&self, other: &TreeSet<T>) -> bool { self.map != other.map }
}
impl<T: Ord + TotalOrd> Ord for TreeSet<T> {
#[inline]
fn lt(&self, other: &TreeSet<T>) -> bool { self.map < other.map }
#[inline]
fn le(&self, other: &TreeSet<T>) -> bool { self.map <= other.map }
#[inline]
fn ge(&self, other: &TreeSet<T>) -> bool { self.map >= other.map }
#[inline]
fn gt(&self, other: &TreeSet<T>) -> bool { self.map > other.map }
}
impl<T: TotalOrd> Container for TreeSet<T> {
/// Return the number of elements in the set
#[inline]
fn len(&self) -> uint { self.map.len() }
/// Return true if the set contains no elements
#[inline]
fn is_empty(&self) -> bool { self.map.is_empty() }
}
impl<T: TotalOrd> Mutable for TreeSet<T> {
/// Clear the set, removing all values.
#[inline]
fn clear(&mut self) { self.map.clear() }
}
impl<T: TotalOrd> Set<T> for TreeSet<T> {
/// Return true if the set contains a value
#[inline]
fn contains(&self, value: &T) -> bool {
self.map.contains_key(value)
}
/// Return true if the set has no elements in common with `other`.
/// This is equivalent to checking for an empty intersection.
fn is_disjoint(&self, other: &TreeSet<T>) -> bool {
self.intersection(other).next().is_none()
}
/// Return true if the set is a subset of another
#[inline]
fn is_subset(&self, other: &TreeSet<T>) -> bool {
other.is_superset(self)
}
/// Return true if the set is a superset of another
fn is_superset(&self, other: &TreeSet<T>) -> bool {
let mut x = self.iter();
let mut y = other.iter();
let mut a = x.next();
let mut b = y.next();
while b.is_some() {
if a.is_none() {
return false
}
let a1 = a.unwrap();
let b1 = b.unwrap();
match a1.cmp(b1) {
Less => (),
Greater => return false,
Equal => b = y.next(),
}
a = x.next();
}
true
}
}
impl<T: TotalOrd> MutableSet<T> for TreeSet<T> {
/// Add a value to the set. Return true if the value was not already
/// present in the set.
#[inline]
fn insert(&mut self, value: T) -> bool { self.map.insert(value, ()) }
/// Remove a value from the set. Return true if the value was
/// present in the set.
#[inline]
fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
}
impl<T: TotalOrd> TreeSet<T> {
/// Create an empty TreeSet
#[inline]
pub fn new() -> TreeSet<T> { TreeSet{map: TreeMap::new()} }
/// Get a lazy iterator over the values in the set.
/// Requires that it be frozen (immutable).
#[inline]
pub fn iter<'a>(&'a self) -> SetItems<'a, T> {
SetItems{iter: self.map.iter()}
}
/// Get a lazy iterator over the values in the set.
/// Requires that it be frozen (immutable).
#[inline]
pub fn rev_iter<'a>(&'a self) -> RevSetItems<'a, T> {
RevSetItems{iter: self.map.rev_iter()}
}
/// Get a lazy iterator pointing to the first value not less than `v` (greater or equal).
/// If all elements in the set are less than `v` empty iterator is returned.
#[inline]
pub fn lower_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
SetItems{iter: self.map.lower_bound(v)}
}
/// Get a lazy iterator pointing to the first value greater than `v`.
/// If all elements in the set are not greater than `v` empty iterator is returned.
#[inline]
pub fn upper_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
SetItems{iter: self.map.upper_bound(v)}
}
/// Visit the values (in-order) representing the difference
pub fn difference<'a>(&'a self, other: &'a TreeSet<T>) -> DifferenceItems<'a, T> {
DifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visit the values (in-order) representing the symmetric difference
pub fn symmetric_difference<'a>(&'a self, other: &'a TreeSet<T>)
-> SymDifferenceItems<'a, T> {
SymDifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visit the values (in-order) representing the intersection
pub fn intersection<'a>(&'a self, other: &'a TreeSet<T>)
-> IntersectionItems<'a, T> {
IntersectionItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visit the values (in-order) representing the union
pub fn union<'a>(&'a self, other: &'a TreeSet<T>) -> UnionItems<'a, T> {
UnionItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
}
/// Lazy forward iterator over a set
pub struct SetItems<'a, T> {
priv iter: Entries<'a, T, ()>
}
/// Lazy backward iterator over a set
pub struct RevSetItems<'a, T> {
priv iter: RevEntries<'a, T, ()>
}
/// Lazy iterator producing elements in the set difference (in-order)
pub struct DifferenceItems<'a, T> {
priv a: Peekable<&'a T, SetItems<'a, T>>,
priv b: Peekable<&'a T, SetItems<'a, T>>,
}
/// Lazy iterator producing elements in the set symmetric difference (in-order)
pub struct SymDifferenceItems<'a, T> {
priv a: Peekable<&'a T, SetItems<'a, T>>,
priv b: Peekable<&'a T, SetItems<'a, T>>,
}
/// Lazy iterator producing elements in the set intersection (in-order)
pub struct IntersectionItems<'a, T> {
priv a: Peekable<&'a T, SetItems<'a, T>>,
priv b: Peekable<&'a T, SetItems<'a, T>>,
}
/// Lazy iterator producing elements in the set intersection (in-order)
pub struct UnionItems<'a, T> {
priv a: Peekable<&'a T, SetItems<'a, T>>,
priv b: Peekable<&'a T, SetItems<'a, T>>,
}
/// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
fn cmp_opt<T: TotalOrd>(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),
}
}
impl<'a, T: TotalOrd> Iterator<&'a T> for DifferenceItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) {
Less => return self.a.next(),
Equal => { self.a.next(); self.b.next(); }
Greater => { self.b.next(); }
}
}
}
}
impl<'a, T: TotalOrd> Iterator<&'a T> for SymDifferenceItems<'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(),
}
}
}
}
impl<'a, T: TotalOrd> Iterator<&'a T> for IntersectionItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
let o_cmp = match (self.a.peek(), self.b.peek()) {
(None , _ ) => None,
(_ , None ) => None,
(Some(a1), Some(b1)) => Some(a1.cmp(b1)),
};
match o_cmp {
None => return None,
Some(Less) => { self.a.next(); }
Some(Equal) => { self.b.next(); return self.a.next() }
Some(Greater) => { self.b.next(); }
}
}
}
}
impl<'a, T: TotalOrd> Iterator<&'a T> for UnionItems<'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.b.next(); return self.a.next() }
Greater => return self.b.next(),
}
}
}
}
// Nodes keep track of their level in the tree, starting at 1 in the
// leaves and with a red child sharing the level of the parent.
#[deriving(Clone)]
struct TreeNode<K, V> {
key: K,
value: V,
left: Option<~TreeNode<K, V>>,
right: Option<~TreeNode<K, V>>,
level: uint
}
impl<K: TotalOrd, V> TreeNode<K, V> {
/// Creates a new tree node.
#[inline]
pub fn new(key: K, value: V) -> TreeNode<K, V> {
TreeNode{key: key, value: value, left: None, right: None, level: 1}
}
}
// Remove left horizontal link by rotating right
fn skew<K: TotalOrd, V>(node: &mut ~TreeNode<K, V>) {
if node.left.as_ref().map_or(false, |x| x.level == node.level) {
let mut save = node.left.take_unwrap();
swap(&mut node.left, &mut save.right); // save.right now None
swap(node, &mut save);
node.right = Some(save);
}
}
// Remove dual horizontal link by rotating left and increasing level of
// the parent
fn split<K: TotalOrd, V>(node: &mut ~TreeNode<K, V>) {
if node.right.as_ref().map_or(false,
|x| x.right.as_ref().map_or(false, |y| y.level == node.level)) {
let mut save = node.right.take_unwrap();
swap(&mut node.right, &mut save.left); // save.left now None
save.level += 1;
swap(node, &mut save);
node.left = Some(save);
}
}
fn find_mut<'r, K: TotalOrd, V>(node: &'r mut Option<~TreeNode<K, V>>,
key: &K)
-> Option<&'r mut V> {
match *node {
Some(ref mut x) => {
match key.cmp(&x.key) {
Less => find_mut(&mut x.left, key),
Greater => find_mut(&mut x.right, key),
Equal => Some(&mut x.value),
}
}
None => None
}
}
fn insert<K: TotalOrd, V>(node: &mut Option<~TreeNode<K, V>>,
key: K, value: V) -> Option<V> {
match *node {
Some(ref mut save) => {
match key.cmp(&save.key) {
Less => {
let inserted = insert(&mut save.left, key, value);
skew(save);
split(save);
inserted
}
Greater => {
let inserted = insert(&mut save.right, key, value);
skew(save);
split(save);
inserted
}
Equal => {
save.key = key;
Some(replace(&mut save.value, value))
}
}
}
None => {
*node = Some(~TreeNode::new(key, value));
None
}
}
}
fn remove<K: TotalOrd, V>(node: &mut Option<~TreeNode<K, V>>,
key: &K) -> Option<V> {
fn heir_swap<K: TotalOrd, V>(node: &mut ~TreeNode<K, V>,
child: &mut Option<~TreeNode<K, V>>) {
// *could* be done without recursion, but it won't borrow check
for x in child.mut_iter() {
if x.right.is_some() {
heir_swap(node, &mut x.right);
} else {
swap(&mut node.key, &mut x.key);
swap(&mut node.value, &mut x.value);
}
}
}
match *node {
None => {
return None; // bottom of tree
}
Some(ref mut save) => {
let (ret, rebalance) = match key.cmp(&save.key) {
Less => (remove(&mut save.left, key), true),
Greater => (remove(&mut save.right, key), true),
Equal => {
if save.left.is_some() {
if save.right.is_some() {
let mut left = save.left.take_unwrap();
if left.right.is_some() {
heir_swap(save, &mut left.right);
} else {
swap(&mut save.key, &mut left.key);
swap(&mut save.value, &mut left.value);
}
save.left = Some(left);
(remove(&mut save.left, key), true)
} else {
let new = save.left.take_unwrap();
let ~TreeNode{value, ..} = replace(save, new);
*save = save.left.take_unwrap();
(Some(value), true)
}
} else if save.right.is_some() {
let new = save.right.take_unwrap();
let ~TreeNode{value, ..} = replace(save, new);
(Some(value), true)
} else {
(None, false)
}
}
};
if rebalance {
let left_level = save.left.as_ref().map_or(0, |x| x.level);
let right_level = save.right.as_ref().map_or(0, |x| x.level);
// re-balance, if necessary
if left_level < save.level - 1 || right_level < save.level - 1 {
save.level -= 1;
if right_level > save.level {
for x in save.right.mut_iter() { x.level = save.level }
}
skew(save);
for right in save.right.mut_iter() {
skew(right);
for x in right.right.mut_iter() { skew(x) }
}
split(save);
for x in save.right.mut_iter() { split(x) }
}
return ret;
}
}
}
return match node.take() {
Some(~TreeNode{value, ..}) => Some(value), None => fail!()
};
}
impl<K: TotalOrd, V> FromIterator<(K, V)> for TreeMap<K, V> {
fn from_iterator<T: Iterator<(K, V)>>(iter: T) -> TreeMap<K, V> {
let mut map = TreeMap::new();
map.extend(iter);
map
}
}
impl<K: TotalOrd, V> Extendable<(K, V)> for TreeMap<K, V> {
#[inline]
fn extend<T: Iterator<(K, V)>>(&mut self, mut iter: T) {
for (k, v) in iter {
self.insert(k, v);
}
}
}
impl<T: TotalOrd> FromIterator<T> for TreeSet<T> {
fn from_iterator<Iter: Iterator<T>>(iter: Iter) -> TreeSet<T> {
let mut set = TreeSet::new();
set.extend(iter);
set
}
}
impl<T: TotalOrd> Extendable<T> for TreeSet<T> {
#[inline]
fn extend<Iter: Iterator<T>>(&mut self, mut iter: Iter) {
for elem in iter {
self.insert(elem);
}
}
}
#[cfg(test)]
mod test_treemap {
use super::{TreeMap, TreeNode};
use rand::Rng;
use rand;
#[test]
fn find_empty() {
let m: TreeMap<int,int> = TreeMap::new();
assert!(m.find(&5) == None);
}
#[test]
fn find_not_found() {
let mut m = TreeMap::new();
assert!(m.insert(1, 2));
assert!(m.insert(5, 3));
assert!(m.insert(9, 3));
assert_eq!(m.find(&2), None);
}
#[test]
fn test_find_mut() {
let mut m = TreeMap::new();
assert!(m.insert(1, 12));
assert!(m.insert(2, 8));
assert!(m.insert(5, 14));
let new = 100;
match m.find_mut(&5) {
None => fail!(), Some(x) => *x = new
}
assert_eq!(m.find(&5), Some(&new));
}
#[test]
fn insert_replace() {
let mut m = TreeMap::new();
assert!(m.insert(5, 2));
assert!(m.insert(2, 9));
assert!(!m.insert(2, 11));
assert_eq!(m.find(&2).unwrap(), &11);
}
#[test]
fn test_clear() {
let mut m = TreeMap::new();
m.clear();
assert!(m.insert(5, 11));
assert!(m.insert(12, -3));
assert!(m.insert(19, 2));
m.clear();
assert!(m.find(&5).is_none());
assert!(m.find(&12).is_none());
assert!(m.find(&19).is_none());
assert!(m.is_empty());
}
#[test]
fn u8_map() {
let mut m = TreeMap::new();
let k1 = "foo".as_bytes();
let k2 = "bar".as_bytes();
let v1 = "baz".as_bytes();
let v2 = "foobar".as_bytes();
m.insert(k1.clone(), v1.clone());
m.insert(k2.clone(), v2.clone());
assert_eq!(m.find(&k2), Some(&v2));
assert_eq!(m.find(&k1), Some(&v1));
}
fn check_equal<K: Eq + TotalOrd, V: Eq>(ctrl: &[(K, V)],
map: &TreeMap<K, V>) {
assert_eq!(ctrl.is_empty(), map.is_empty());
for x in ctrl.iter() {
let &(ref k, ref v) = x;
assert!(map.find(k).unwrap() == v)
}
for (map_k, map_v) in map.iter() {
let mut found = false;
for x in ctrl.iter() {
let &(ref ctrl_k, ref ctrl_v) = x;
if *map_k == *ctrl_k {
assert!(*map_v == *ctrl_v);
found = true;
break;
}
}
assert!(found);
}
}
fn check_left<K: TotalOrd, V>(node: &Option<~TreeNode<K, V>>,
parent: &~TreeNode<K, V>) {
match *node {
Some(ref r) => {
assert_eq!(r.key.cmp(&parent.key), Less);
assert!(r.level == parent.level - 1); // left is black
check_left(&r.left, r);
check_right(&r.right, r, false);
}
None => assert!(parent.level == 1) // parent is leaf
}
}
fn check_right<K: TotalOrd, V>(node: &Option<~TreeNode<K, V>>,
parent: &~TreeNode<K, V>,
parent_red: bool) {
match *node {
Some(ref r) => {
assert_eq!(r.key.cmp(&parent.key), Greater);
let red = r.level == parent.level;
if parent_red { assert!(!red) } // no dual horizontal links
// Right red or black
assert!(red || r.level == parent.level - 1);
check_left(&r.left, r);
check_right(&r.right, r, red);
}
None => assert!(parent.level == 1) // parent is leaf
}
}
fn check_structure<K: TotalOrd, V>(map: &TreeMap<K, V>) {
match map.root {
Some(ref r) => {
check_left(&r.left, r);
check_right(&r.right, r, false);
}
None => ()
}
}
#[test]
fn test_rand_int() {
let mut map: TreeMap<int,int> = TreeMap::new();
let mut ctrl = ~[];
check_equal(ctrl, &map);
assert!(map.find(&5).is_none());
let mut rng: rand::IsaacRng = rand::SeedableRng::from_seed(&[42]);
for _ in range(0, 3) {
for _ in range(0, 90) {
let k = rng.gen();
let v = rng.gen();
if !ctrl.iter().any(|x| x == &(k, v)) {
assert!(map.insert(k, v));
ctrl.push((k, v));
check_structure(&map);
check_equal(ctrl, &map);
}
}
for _ in range(0, 30) {
let r = rng.gen_range(0, ctrl.len());
let (key, _) = ctrl.remove(r).unwrap();
assert!(map.remove(&key));
check_structure(&map);
check_equal(ctrl, &map);
}
}
}
#[test]
fn test_len() {
let mut m = TreeMap::new();
assert!(m.insert(3, 6));
assert_eq!(m.len(), 1);
assert!(m.insert(0, 0));
assert_eq!(m.len(), 2);
assert!(m.insert(4, 8));
assert_eq!(m.len(), 3);
assert!(m.remove(&3));
assert_eq!(m.len(), 2);
assert!(!m.remove(&5));
assert_eq!(m.len(), 2);
assert!(m.insert(2, 4));
assert_eq!(m.len(), 3);
assert!(m.insert(1, 2));
assert_eq!(m.len(), 4);
}
#[test]
fn test_iterator() {
let mut m = TreeMap::new();
assert!(m.insert(3, 6));
assert!(m.insert(0, 0));
assert!(m.insert(4, 8));
assert!(m.insert(2, 4));
assert!(m.insert(1, 2));
let mut n = 0;
for (k, v) in m.iter() {
assert_eq!(*k, n);
assert_eq!(*v, n * 2);
n += 1;
}
assert_eq!(n, 5);
}
#[test]
fn test_interval_iteration() {
let mut m = TreeMap::new();
for i in range(1, 100) {
assert!(m.insert(i * 2, i * 4));
}
for i in range(1, 198) {
let mut lb_it = m.lower_bound(&i);
let (&k, &v) = lb_it.next().unwrap();
let lb = i + i % 2;
assert_eq!(lb, k);
assert_eq!(lb * 2, v);
let mut ub_it = m.upper_bound(&i);
let (&k, &v) = ub_it.next().unwrap();
let ub = i + 2 - i % 2;
assert_eq!(ub, k);
assert_eq!(ub * 2, v);
}
let mut end_it = m.lower_bound(&199);
assert_eq!(end_it.next(), None);
}
#[test]
fn test_rev_iter() {
let mut m = TreeMap::new();
assert!(m.insert(3, 6));
assert!(m.insert(0, 0));
assert!(m.insert(4, 8));
assert!(m.insert(2, 4));
assert!(m.insert(1, 2));
let mut n = 4;
for (k, v) in m.rev_iter() {
assert_eq!(*k, n);
assert_eq!(*v, n * 2);
n -= 1;
}
}
#[test]
fn test_mut_iter() {
let mut m = TreeMap::new();
for i in range(0u, 10) {
assert!(m.insert(i, 100 * i));
}
for (i, (&k, v)) in m.mut_iter().enumerate() {
*v += k * 10 + i; // 000 + 00 + 0, 100 + 10 + 1, ...
}
for (&k, &v) in m.iter() {
assert_eq!(v, 111 * k);
}
}
#[test]
fn test_mut_rev_iter() {
let mut m = TreeMap::new();
for i in range(0u, 10) {
assert!(m.insert(i, 100 * i));
}
for (i, (&k, v)) in m.mut_rev_iter().enumerate() {
*v += k * 10 + (9 - i); // 900 + 90 + (9 - 0), 800 + 80 + (9 - 1), ...
}
for (&k, &v) in m.iter() {
assert_eq!(v, 111 * k);
}
}
#[test]
fn test_mut_interval_iter() {
let mut m_lower = TreeMap::new();
let mut m_upper = TreeMap::new();
for i in range(1, 100) {
assert!(m_lower.insert(i * 2, i * 4));
assert!(m_upper.insert(i * 2, i * 4));
}
for i in range(1, 199) {
let mut lb_it = m_lower.mut_lower_bound(&i);
let (&k, v) = lb_it.next().unwrap();
let lb = i + i % 2;
assert_eq!(lb, k);
*v -= k;
}
for i in range(0, 198) {
let mut ub_it = m_upper.mut_upper_bound(&i);
let (&k, v) = ub_it.next().unwrap();
let ub = i + 2 - i % 2;
assert_eq!(ub, k);
*v -= k;
}
assert!(m_lower.mut_lower_bound(&199).next().is_none());
assert!(m_upper.mut_upper_bound(&198).next().is_none());
assert!(m_lower.iter().all(|(_, &x)| x == 0));
assert!(m_upper.iter().all(|(_, &x)| x == 0));
}
#[test]
fn test_eq() {
let mut a = TreeMap::new();
let mut b = TreeMap::new();
assert!(a == b);
assert!(a.insert(0, 5));
assert!(a != b);
assert!(b.insert(0, 4));
assert!(a != b);
assert!(a.insert(5, 19));
assert!(a != b);
assert!(!b.insert(0, 5));
assert!(a != b);
assert!(b.insert(5, 19));
assert!(a == b);
}
#[test]
fn test_lt() {
let mut a = TreeMap::new();
let mut b = TreeMap::new();
assert!(!(a < b) && !(b < a));
assert!(b.insert(0, 5));
assert!(a < b);
assert!(a.insert(0, 7));
assert!(!(a < b) && b < a);
assert!(b.insert(-2, 0));
assert!(b < a);
assert!(a.insert(-5, 2));
assert!(a < b);
assert!(a.insert(6, 2));
assert!(a < b && !(b < a));
}
#[test]
fn test_ord() {
let mut a = TreeMap::new();
let mut b = TreeMap::new();
assert!(a <= b && a >= b);
assert!(a.insert(1, 1));
assert!(a > b && a >= b);
assert!(b < a && b <= a);
assert!(b.insert(2, 2));
assert!(b > a && b >= a);
assert!(a < b && a <= b);
}
#[test]
fn test_lazy_iterator() {
let mut m = TreeMap::new();
let (x1, y1) = (2, 5);
let (x2, y2) = (9, 12);
let (x3, y3) = (20, -3);
let (x4, y4) = (29, 5);
let (x5, y5) = (103, 3);
assert!(m.insert(x1, y1));
assert!(m.insert(x2, y2));
assert!(m.insert(x3, y3));
assert!(m.insert(x4, y4));
assert!(m.insert(x5, y5));
let m = m;
let mut a = m.iter();
assert_eq!(a.next().unwrap(), (&x1, &y1));
assert_eq!(a.next().unwrap(), (&x2, &y2));
assert_eq!(a.next().unwrap(), (&x3, &y3));
assert_eq!(a.next().unwrap(), (&x4, &y4));
assert_eq!(a.next().unwrap(), (&x5, &y5));
assert!(a.next().is_none());
let mut b = m.iter();
let expected = [(&x1, &y1), (&x2, &y2), (&x3, &y3), (&x4, &y4),
(&x5, &y5)];
let mut i = 0;
for x in b {
assert_eq!(expected[i], x);
i += 1;
if i == 2 {
break
}
}
for x in b {
assert_eq!(expected[i], x);
i += 1;
}
}
#[test]
fn test_from_iter() {
let xs = ~[(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
let map: TreeMap<int, int> = xs.iter().map(|&x| x).collect();
for &(k, v) in xs.iter() {
assert_eq!(map.find(&k), Some(&v));
}
}
}
#[cfg(test)]
mod bench {
extern crate test;
use self::test::BenchHarness;
use super::TreeMap;
use deque::bench::{insert_rand_n, insert_seq_n, find_rand_n, find_seq_n};
// Find seq
#[bench]
pub fn insert_rand_100(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
insert_rand_n(100, &mut m, bh);
}
#[bench]
pub fn insert_rand_10_000(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
insert_rand_n(10_000, &mut m, bh);
}
// Insert seq
#[bench]
pub fn insert_seq_100(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
insert_seq_n(100, &mut m, bh);
}
#[bench]
pub fn insert_seq_10_000(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
insert_seq_n(10_000, &mut m, bh);
}
// Find rand
#[bench]
pub fn find_rand_100(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
find_rand_n(100, &mut m, bh);
}
#[bench]
pub fn find_rand_10_000(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
find_rand_n(10_000, &mut m, bh);
}
// Find seq
#[bench]
pub fn find_seq_100(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
find_seq_n(100, &mut m, bh);
}
#[bench]
pub fn find_seq_10_000(bh: &mut BenchHarness) {
let mut m : TreeMap<uint,uint> = TreeMap::new();
find_seq_n(10_000, &mut m, bh);
}
}
#[cfg(test)]
mod test_set {
use super::{TreeMap, TreeSet};
#[test]
fn test_clear() {
let mut s = TreeSet::new();
s.clear();
assert!(s.insert(5));
assert!(s.insert(12));
assert!(s.insert(19));
s.clear();
assert!(!s.contains(&5));
assert!(!s.contains(&12));
assert!(!s.contains(&19));
assert!(s.is_empty());
}
#[test]
fn test_disjoint() {
let mut xs = TreeSet::new();
let mut ys = TreeSet::new();
assert!(xs.is_disjoint(&ys));
assert!(ys.is_disjoint(&xs));
assert!(xs.insert(5));
assert!(ys.insert(11));
assert!(xs.is_disjoint(&ys));
assert!(ys.is_disjoint(&xs));
assert!(xs.insert(7));
assert!(xs.insert(19));
assert!(xs.insert(4));
assert!(ys.insert(2));
assert!(ys.insert(-11));
assert!(xs.is_disjoint(&ys));
assert!(ys.is_disjoint(&xs));
assert!(ys.insert(7));
assert!(!xs.is_disjoint(&ys));
assert!(!ys.is_disjoint(&xs));
}
#[test]
fn test_subset_and_superset() {
let mut a = TreeSet::new();
assert!(a.insert(0));
assert!(a.insert(5));
assert!(a.insert(11));
assert!(a.insert(7));
let mut b = TreeSet::new();
assert!(b.insert(0));
assert!(b.insert(7));
assert!(b.insert(19));
assert!(b.insert(250));
assert!(b.insert(11));
assert!(b.insert(200));
assert!(!a.is_subset(&b));
assert!(!a.is_superset(&b));
assert!(!b.is_subset(&a));
assert!(!b.is_superset(&a));
assert!(b.insert(5));
assert!(a.is_subset(&b));
assert!(!a.is_superset(&b));
assert!(!b.is_subset(&a));
assert!(b.is_superset(&a));
}
#[test]
fn test_iterator() {
let mut m = TreeSet::new();
assert!(m.insert(3));
assert!(m.insert(0));
assert!(m.insert(4));
assert!(m.insert(2));
assert!(m.insert(1));
let mut n = 0;
for x in m.iter() {
assert_eq!(*x, n);
n += 1
}
}
#[test]
fn test_rev_iter() {
let mut m = TreeSet::new();
assert!(m.insert(3));
assert!(m.insert(0));
assert!(m.insert(4));
assert!(m.insert(2));
assert!(m.insert(1));
let mut n = 4;
for x in m.rev_iter() {
assert_eq!(*x, n);
n -= 1;
}
}
#[test]
fn test_clone_eq() {
let mut m = TreeSet::new();
m.insert(1);
m.insert(2);
assert!(m.clone() == m);
}
fn check(a: &[int],
b: &[int],
expected: &[int],
f: |&TreeSet<int>, &TreeSet<int>, f: |&int| -> bool| -> bool) {
let mut set_a = TreeSet::new();
let mut set_b = TreeSet::new();
for x in a.iter() { assert!(set_a.insert(*x)) }
for y in b.iter() { assert!(set_b.insert(*y)) }
let mut i = 0;
f(&set_a, &set_b, |x| {
assert_eq!(*x, expected[i]);
i += 1;
true
});
assert_eq!(i, expected.len());
}
#[test]
fn test_intersection() {
fn check_intersection(a: &[int], b: &[int], expected: &[int]) {
check(a, b, expected, |x, y, f| x.intersection(y).advance(f))
}
check_intersection([], [], []);
check_intersection([1, 2, 3], [], []);
check_intersection([], [1, 2, 3], []);
check_intersection([2], [1, 2, 3], [2]);
check_intersection([1, 2, 3], [2], [2]);
check_intersection([11, 1, 3, 77, 103, 5, -5],
[2, 11, 77, -9, -42, 5, 3],
[3, 5, 11, 77]);
}
#[test]
fn test_difference() {
fn check_difference(a: &[int], b: &[int], expected: &[int]) {
check(a, b, expected, |x, y, f| x.difference(y).advance(f))
}
check_difference([], [], []);
check_difference([1, 12], [], [1, 12]);
check_difference([], [1, 2, 3, 9], []);
check_difference([1, 3, 5, 9, 11],
[3, 9],
[1, 5, 11]);
check_difference([-5, 11, 22, 33, 40, 42],
[-12, -5, 14, 23, 34, 38, 39, 50],
[11, 22, 33, 40, 42]);
}
#[test]
fn test_symmetric_difference() {
fn check_symmetric_difference(a: &[int], b: &[int],
expected: &[int]) {
check(a, b, expected, |x, y, f| x.symmetric_difference(y).advance(f))
}
check_symmetric_difference([], [], []);
check_symmetric_difference([1, 2, 3], [2], [1, 3]);
check_symmetric_difference([2], [1, 2, 3], [1, 3]);
check_symmetric_difference([1, 3, 5, 9, 11],
[-2, 3, 9, 14, 22],
[-2, 1, 5, 11, 14, 22]);
}
#[test]
fn test_union() {
fn check_union(a: &[int], b: &[int],
expected: &[int]) {
check(a, b, expected, |x, y, f| x.union(y).advance(f))
}
check_union([], [], []);
check_union([1, 2, 3], [2], [1, 2, 3]);
check_union([2], [1, 2, 3], [1, 2, 3]);
check_union([1, 3, 5, 9, 11, 16, 19, 24],
[-2, 1, 5, 9, 13, 19],
[-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]);
}
#[test]
fn test_zip() {
let mut x = TreeSet::new();
x.insert(5u);
x.insert(12u);
x.insert(11u);
let mut y = TreeSet::new();
y.insert("foo");
y.insert("bar");
let x = x;
let y = y;
let mut z = x.iter().zip(y.iter());
// FIXME: #5801: this needs a type hint to compile...
let result: Option<(&uint, & &'static str)> = z.next();
assert_eq!(result.unwrap(), (&5u, & &"bar"));
let result: Option<(&uint, & &'static str)> = z.next();
assert_eq!(result.unwrap(), (&11u, & &"foo"));
let result: Option<(&uint, & &'static str)> = z.next();
assert!(result.is_none());
}
#[test]
fn test_swap() {
let mut m = TreeMap::new();
assert_eq!(m.swap(1, 2), None);
assert_eq!(m.swap(1, 3), Some(2));
assert_eq!(m.swap(1, 4), Some(3));
}
#[test]
fn test_pop() {
let mut m = TreeMap::new();
m.insert(1, 2);
assert_eq!(m.pop(&1), Some(2));
assert_eq!(m.pop(&1), None);
}
#[test]
fn test_from_iter() {
let xs = ~[1, 2, 3, 4, 5, 6, 7, 8, 9];
let set: TreeSet<int> = xs.iter().map(|&x| x).collect();
for x in xs.iter() {
assert!(set.contains(x));
}
}
}