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/Rust

Struct collections::binary_heap::BinaryHeap

pub struct BinaryHeap<T> { /* fields omitted */ }

A priority queue implemented with a binary heap.

This will be a max-heap.

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 heap. This is normally only possible through Cell, RefCell, global state, I/O, or unsafe code.

Examples

use std::collections::BinaryHeap;

// Type inference lets us omit an explicit type signature (which
// would be `BinaryHeap<i32>` in this example).
let mut heap = BinaryHeap::new();

// We can use peek to look at the next item in the heap. In this case,
// there's no items in there yet so we get None.
assert_eq!(heap.peek(), None);

// Let's add some scores...
heap.push(1);
heap.push(5);
heap.push(2);

// Now peek shows the most important item in the heap.
assert_eq!(heap.peek(), Some(&5));

// We can check the length of a heap.
assert_eq!(heap.len(), 3);

// We can iterate over the items in the heap, although they are returned in
// a random order.
for x in &heap {
    println!("{}", x);
}

// If we instead pop these scores, they should come back in order.
assert_eq!(heap.pop(), Some(5));
assert_eq!(heap.pop(), Some(2));
assert_eq!(heap.pop(), Some(1));
assert_eq!(heap.pop(), None);

// We can clear the heap of any remaining items.
heap.clear();

// The heap should now be empty.
assert!(heap.is_empty())

Methods

`impl<T: Ord> BinaryHeap<T>` [src]

`fn new() -> BinaryHeap<T>`

Creates an empty BinaryHeap as a max-heap.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
heap.push(4);

`fn with_capacity(capacity: usize) -> BinaryHeap<T>`

Creates an empty BinaryHeap with a specific capacity. This preallocates enough memory for capacity elements, so that the BinaryHeap does not have to be reallocated until it contains at least that many values.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::with_capacity(10);
heap.push(4);

`fn iter(&self) -> Iter<T>`

Returns an iterator visiting all values in the underlying vector, in arbitrary order.

Examples

Basic usage:

use std::collections::BinaryHeap;
let heap = BinaryHeap::from(vec![1, 2, 3, 4]);

// Print 1, 2, 3, 4 in arbitrary order
for x in heap.iter() {
    println!("{}", x);
}

`fn peek(&self) -> Option<&T>`

Returns the greatest item in the binary heap, or None if it is empty.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
assert_eq!(heap.peek(), None);

heap.push(1);
heap.push(5);
heap.push(2);
assert_eq!(heap.peek(), Some(&5));

`fn peek_mut(&mut self) -> Option<PeekMut<T>>`
1.12.0

Returns a mutable reference to the greatest item in the binary heap, or None if it is empty.

Note: If the PeekMut value is leaked, the heap may be in an inconsistent state.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
assert!(heap.peek_mut().is_none());

heap.push(1);
heap.push(5);
heap.push(2);
{
    let mut val = heap.peek_mut().unwrap();
    *val = 0;
}
assert_eq!(heap.peek(), Some(&2));

`fn capacity(&self) -> usize`

Returns the number of elements the binary heap can hold without reallocating.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::with_capacity(100);
assert!(heap.capacity() >= 100);
heap.push(4);

`fn reserve_exact(&mut self, additional: usize)`

Reserves the minimum capacity for exactly additional more elements to be inserted in the given BinaryHeap. Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore capacity can not be relied upon to be precisely minimal. Prefer reserve if future insertions are expected.

Panics

Panics if the new capacity overflows usize.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
heap.reserve_exact(100);
assert!(heap.capacity() >= 100);
heap.push(4);

`fn reserve(&mut self, additional: usize)`

Reserves capacity for at least additional more elements to be inserted in the BinaryHeap. The collection may reserve more space to avoid frequent reallocations.

Panics

Panics if the new capacity overflows usize.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
heap.reserve(100);
assert!(heap.capacity() >= 100);
heap.push(4);

`fn shrink_to_fit(&mut self)`

Discards as much additional capacity as possible.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap: BinaryHeap<i32> = BinaryHeap::with_capacity(100);

assert!(heap.capacity() >= 100);
heap.shrink_to_fit();
assert!(heap.capacity() == 0);

`fn pop(&mut self) -> Option<T>`

Removes the greatest item from the binary heap and returns it, or None if it is empty.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::from(vec![1, 3]);

assert_eq!(heap.pop(), Some(3));
assert_eq!(heap.pop(), Some(1));
assert_eq!(heap.pop(), None);

`fn push(&mut self, item: T)`

Pushes an item onto the binary heap.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
heap.push(3);
heap.push(5);
heap.push(1);

assert_eq!(heap.len(), 3);
assert_eq!(heap.peek(), Some(&5));

`fn push_pop(&mut self, item: T) -> T`

Deprecated since 1.13.0: use peek_mut instead 🔬 This is a nightly-only experimental API. (binary_heap_extras #28147)needs to be audited

Pushes an item onto the binary heap, then pops the greatest item off the queue in an optimized fashion.

Examples

Basic usage:

#![feature(binary_heap_extras)]
#![allow(deprecated)]

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
heap.push(1);
heap.push(5);

assert_eq!(heap.push_pop(3), 5);
assert_eq!(heap.push_pop(9), 9);
assert_eq!(heap.len(), 2);
assert_eq!(heap.peek(), Some(&3));

`fn replace(&mut self, item: T) -> Option<T>`

Deprecated since 1.13.0: use peek_mut instead 🔬 This is a nightly-only experimental API. (binary_heap_extras #28147)needs to be audited

Pops the greatest item off the binary heap, then pushes an item onto the queue in an optimized fashion. The push is done regardless of whether the binary heap was empty.

Examples

Basic usage:

#![feature(binary_heap_extras)]
#![allow(deprecated)]

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();

assert_eq!(heap.replace(1), None);
assert_eq!(heap.replace(3), Some(1));
assert_eq!(heap.len(), 1);
assert_eq!(heap.peek(), Some(&3));

`fn into_vec(self) -> Vec<T>`
1.5.0

Consumes the BinaryHeap and returns the underlying vector in arbitrary order.

Examples

Basic usage:

use std::collections::BinaryHeap;
let heap = BinaryHeap::from(vec![1, 2, 3, 4, 5, 6, 7]);
let vec = heap.into_vec();

// Will print in some order
for x in vec {
    println!("{}", x);
}

`fn into_sorted_vec(self) -> Vec<T>`
1.5.0

Consumes the BinaryHeap and returns a vector in sorted (ascending) order.

Examples

Basic usage:

use std::collections::BinaryHeap;

let mut heap = BinaryHeap::from(vec![1, 2, 4, 5, 7]);
heap.push(6);
heap.push(3);

let vec = heap.into_sorted_vec();
assert_eq!(vec, [1, 2, 3, 4, 5, 6, 7]);

`fn len(&self) -> usize`

Returns the length of the binary heap.

Examples

Basic usage:

use std::collections::BinaryHeap;
let heap = BinaryHeap::from(vec![1, 3]);

assert_eq!(heap.len(), 2);

`fn is_empty(&self) -> bool`

Checks if the binary heap is empty.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();

assert!(heap.is_empty());

heap.push(3);
heap.push(5);
heap.push(1);

assert!(!heap.is_empty());

`fn drain(&mut self) -> Drain<T>`
1.6.0

Clears the binary heap, returning an iterator over the removed elements.

The elements are removed in arbitrary order.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::from(vec![1, 3]);

assert!(!heap.is_empty());

for x in heap.drain() {
    println!("{}", x);
}

assert!(heap.is_empty());

`fn clear(&mut self)`

Drops all items from the binary heap.

Examples

Basic usage:

use std::collections::BinaryHeap;
let mut heap = BinaryHeap::from(vec![1, 3]);

assert!(!heap.is_empty());

heap.clear();

assert!(heap.is_empty());

`fn append(&mut self, other: &mut Self)`
1.11.0

Moves all the elements of other into self, leaving other empty.

Examples

Basic usage:

use std::collections::BinaryHeap;

let v = vec![-10, 1, 2, 3, 3];
let mut a = BinaryHeap::from(v);

let v = vec![-20, 5, 43];
let mut b = BinaryHeap::from(v);

a.append(&mut b);

assert_eq!(a.into_sorted_vec(), [-20, -10, 1, 2, 3, 3, 5, 43]);
assert!(b.is_empty());

Trait Implementations

`impl<T: Clone> Clone for BinaryHeap<T>` [src]

`fn clone(&self) -> Self`

Returns a copy of the value. Read more

`fn clone_from(&mut self, source: &Self)`

Performs copy-assignment from source. Read more

`impl<T: Ord> Default for BinaryHeap<T>` [src]

`fn default() -> BinaryHeap<T>`

Creates an empty BinaryHeap<T>.

`impl<T: Debug + Ord> Debug for BinaryHeap<T>`
1.4.0
[src]

`fn fmt(&self, f: &mut Formatter) -> Result`

Formats the value using the given formatter.

`impl<T: Ord> From<Vec<T>> for BinaryHeap<T>` [src]

`fn from(vec: Vec<T>) -> BinaryHeap<T>`

Performs the conversion.

`impl<T: Ord> FromIterator<T> for BinaryHeap<T>` [src]

`fn from_iter<I: IntoIterator<Item=T>>(iter: I) -> BinaryHeap<T>`

Creates a value from an iterator. Read more

`impl<T: Ord> IntoIterator for BinaryHeap<T>` [src]

`type Item = T`

The type of the elements being iterated over.

`type IntoIter = IntoIter<T>`

Which kind of iterator are we turning this into?

`fn into_iter(self) -> IntoIter<T>`

Creates a consuming iterator, that is, one that moves each value out of the binary heap in arbitrary order. The binary heap cannot be used after calling this.

Examples

Basic usage:

use std::collections::BinaryHeap;
let heap = BinaryHeap::from(vec![1, 2, 3, 4]);

// Print 1, 2, 3, 4 in arbitrary order
for x in heap.into_iter() {
    // x has type i32, not &i32
    println!("{}", x);
}

`impl<'a, T> IntoIterator for &'a BinaryHeap<T> where T: Ord` [src]

`type Item = &'a T`

The type of the elements being iterated over.

`type IntoIter = Iter<'a, T>`

Which kind of iterator are we turning this into?

`fn into_iter(self) -> Iter<'a, T>`

Creates an iterator from a value. Read more

`impl<T: Ord> Extend<T> for BinaryHeap<T>` [src]

`fn extend<I: IntoIterator<Item=T>>(&mut self, iter: I)`

Extends a collection with the contents of an iterator. Read more

`impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BinaryHeap<T>`
1.2.0
[src]

`fn extend<I: IntoIterator<Item=&'a T>>(&mut self, iter: I)`

Extends a collection with the contents of an iterator. Read more

`impl<'a, T: 'a> Placer<T> for &'a mut BinaryHeap<T> where T: Clone + Ord` [src]

`type Place = BinaryHeapPlace<'a, T>`

🔬 This is a nightly-only experimental API. (placement_new_protocol #27779)

Place is the intermedate agent guarding the uninitialized state for Data. Read more

`fn make_place(self) -> Self::Place`

🔬 This is a nightly-only experimental API. (placement_new_protocol #27779)

Creates a fresh place from self.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/collections/binary_heap/struct.BinaryHeap.html

Struct collections::binary_heap::BinaryHeap

Examples

Methods

impl<T: Ord> BinaryHeap<T> [src]

fn new() -> BinaryHeap<T>

Examples

fn with_capacity(capacity: usize) -> BinaryHeap<T>

Examples

fn iter(&self) -> Iter<T>

Examples

fn peek(&self) -> Option<&T>

Examples

fn peek_mut(&mut self) -> Option<PeekMut<T>>1.12.0

Examples

fn capacity(&self) -> usize

Examples

fn reserve_exact(&mut self, additional: usize)

Panics

Examples

fn reserve(&mut self, additional: usize)

Panics

Examples

fn shrink_to_fit(&mut self)

Examples

fn pop(&mut self) -> Option<T>

Examples

fn push(&mut self, item: T)

Examples

fn push_pop(&mut self, item: T) -> T

Examples

fn replace(&mut self, item: T) -> Option<T>

Examples

fn into_vec(self) -> Vec<T>1.5.0

Examples

fn into_sorted_vec(self) -> Vec<T>1.5.0

Examples

fn len(&self) -> usize

Examples

fn is_empty(&self) -> bool

Examples

fn drain(&mut self) -> Drain<T>1.6.0

Examples

fn clear(&mut self)

Examples

fn append(&mut self, other: &mut Self)1.11.0

Examples

Trait Implementations

impl<T: Clone> Clone for BinaryHeap<T> [src]

fn clone(&self) -> Self

fn clone_from(&mut self, source: &Self)

impl<T: Ord> Default for BinaryHeap<T> [src]

fn default() -> BinaryHeap<T>

impl<T: Debug + Ord> Debug for BinaryHeap<T> 1.4.0 [src]

fn fmt(&self, f: &mut Formatter) -> Result

impl<T: Ord> From<Vec<T>> for BinaryHeap<T> [src]

fn from(vec: Vec<T>) -> BinaryHeap<T>

impl<T: Ord> FromIterator<T> for BinaryHeap<T> [src]

fn from_iter<I: IntoIterator<Item=T>>(iter: I) -> BinaryHeap<T>

impl<T: Ord> IntoIterator for BinaryHeap<T> [src]

type Item = T

type IntoIter = IntoIter<T>

fn into_iter(self) -> IntoIter<T>

Examples

impl<'a, T> IntoIterator for &'a BinaryHeap<T> where T: Ord [src]

type Item = &'a T

type IntoIter = Iter<'a, T>

fn into_iter(self) -> Iter<'a, T>

impl<T: Ord> Extend<T> for BinaryHeap<T> [src]

fn extend<I: IntoIterator<Item=T>>(&mut self, iter: I)

impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BinaryHeap<T> 1.2.0 [src]

fn extend<I: IntoIterator<Item=&'a T>>(&mut self, iter: I)

impl<'a, T: 'a> Placer<T> for &'a mut BinaryHeap<T> where T: Clone + Ord [src]

type Place = BinaryHeapPlace<'a, T>

fn make_place(self) -> Self::Place

`impl<T: Ord> BinaryHeap<T>` [src]

`fn new() -> BinaryHeap<T>`

`fn with_capacity(capacity: usize) -> BinaryHeap<T>`

`fn iter(&self) -> Iter<T>`

`fn peek(&self) -> Option<&T>`

`fn peek_mut(&mut self) -> Option<PeekMut<T>>`
1.12.0

`fn capacity(&self) -> usize`

`fn reserve_exact(&mut self, additional: usize)`

`fn reserve(&mut self, additional: usize)`

`fn shrink_to_fit(&mut self)`

`fn pop(&mut self) -> Option<T>`

`fn push(&mut self, item: T)`

`fn push_pop(&mut self, item: T) -> T`

`fn replace(&mut self, item: T) -> Option<T>`

`fn into_vec(self) -> Vec<T>`
1.5.0

`fn into_sorted_vec(self) -> Vec<T>`
1.5.0

`fn len(&self) -> usize`

`fn is_empty(&self) -> bool`

`fn drain(&mut self) -> Drain<T>`
1.6.0

`fn clear(&mut self)`

`fn append(&mut self, other: &mut Self)`
1.11.0

`impl<T: Clone> Clone for BinaryHeap<T>` [src]

`fn clone(&self) -> Self`

`fn clone_from(&mut self, source: &Self)`

`impl<T: Ord> Default for BinaryHeap<T>` [src]

`fn default() -> BinaryHeap<T>`

`impl<T: Debug + Ord> Debug for BinaryHeap<T>`
1.4.0
[src]

`fn fmt(&self, f: &mut Formatter) -> Result`

`impl<T: Ord> From<Vec<T>> for BinaryHeap<T>` [src]

`fn from(vec: Vec<T>) -> BinaryHeap<T>`

`impl<T: Ord> FromIterator<T> for BinaryHeap<T>` [src]

`fn from_iter<I: IntoIterator<Item=T>>(iter: I) -> BinaryHeap<T>`

`impl<T: Ord> IntoIterator for BinaryHeap<T>` [src]

`type Item = T`

`type IntoIter = IntoIter<T>`

`fn into_iter(self) -> IntoIter<T>`

`impl<'a, T> IntoIterator for &'a BinaryHeap<T> where T: Ord` [src]

`type Item = &'a T`

`type IntoIter = Iter<'a, T>`

`fn into_iter(self) -> Iter<'a, T>`

`impl<T: Ord> Extend<T> for BinaryHeap<T>` [src]

`fn extend<I: IntoIterator<Item=T>>(&mut self, iter: I)`

`impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BinaryHeap<T>`
1.2.0
[src]

`fn extend<I: IntoIterator<Item=&'a T>>(&mut self, iter: I)`

`impl<'a, T: 'a> Placer<T> for &'a mut BinaryHeap<T> where T: Clone + Ord` [src]

`type Place = BinaryHeapPlace<'a, T>`

`fn make_place(self) -> Self::Place`