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.
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()) impl<T> BinaryHeap<T> where
T: Ord,
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fn new() -> BinaryHeap<T>
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Creates an empty BinaryHeap as a max-heap.
Basic usage:
use std::collections::BinaryHeap; let mut heap = BinaryHeap::new(); heap.push(4);
fn with_capacity(capacity: usize) -> BinaryHeap<T>
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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.
Basic usage:
use std::collections::BinaryHeap; let mut heap = BinaryHeap::with_capacity(10); heap.push(4);
fn iter(&self) -> Iter<T>
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Returns an iterator visiting all values in the underlying vector, in arbitrary order.
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>
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Returns the greatest item in the binary heap, or None if it is empty.
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>>
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.
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
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Returns the number of elements the binary heap can hold without reallocating.
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)
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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 if the new capacity overflows usize.
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)
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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 if the new capacity overflows usize.
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)
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Discards as much additional capacity as possible.
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>
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Removes the greatest item from the binary heap and returns it, or None if it is empty.
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)
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Pushes an item onto the binary heap.
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 into_vec(self) -> Vec<T>
Consumes the BinaryHeap and returns the underlying vector in arbitrary order.
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>
Consumes the BinaryHeap and returns a vector in sorted (ascending) order.
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
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Returns the length of the binary heap.
Basic usage:
use std::collections::BinaryHeap; let heap = BinaryHeap::from(vec![1, 3]); assert_eq!(heap.len(), 2);
fn is_empty(&self) -> bool
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Checks if the binary heap is empty.
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>
Clears the binary heap, returning an iterator over the removed elements.
The elements are removed in arbitrary order.
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)
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Drops all items from the binary heap.
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 BinaryHeap<T>)
Moves all the elements of other into self, leaving other empty.
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());
impl<T> From<BinaryHeap<T>> for Vec<T>
fn from(heap: BinaryHeap<T>) -> Vec<T>
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Performs the conversion.
impl<T> From<Vec<T>> for BinaryHeap<T> where
T: Ord,
fn from(vec: Vec<T>) -> BinaryHeap<T>
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Performs the conversion.
impl<'a, T> IntoIterator for &'a BinaryHeap<T> where
T: Ord,
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type Item = &'a TThe 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>
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Creates an iterator from a value. Read more
impl<T> IntoIterator for BinaryHeap<T> where
T: Ord,
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type Item = TThe 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>
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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.
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> Placer<T> for &'a mut BinaryHeap<T> where
T: 'a + Clone + Ord,
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type Place = BinaryHeapPlace<'a, T>Place is the intermediate agent guarding the uninitialized state for Data. Read more
fn make_place(self) -> <&'a mut BinaryHeap<T> as Placer<T>>::Place
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Creates a fresh place from self.
impl<T> Default for BinaryHeap<T> where
T: Ord,
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fn default() -> BinaryHeap<T>
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Creates an empty BinaryHeap<T>.
impl<T> Debug for BinaryHeap<T> where
T: Ord + Debug,
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
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Formats the value using the given formatter. Read more
impl<T> FromIterator<T> for BinaryHeap<T> where
T: Ord,
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fn from_iter<I>(iter: I) -> BinaryHeap<T> where
I: IntoIterator<Item = T>,
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Creates a value from an iterator. Read more
impl<T> Extend<T> for BinaryHeap<T> where
T: Ord,
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = T>,
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Extends a collection with the contents of an iterator. Read more
impl<'a, T> Extend<&'a T> for BinaryHeap<T> where
T: 'a + Copy + Ord,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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Extends a collection with the contents of an iterator. Read more
impl<T> Clone for BinaryHeap<T> where
T: Clone,
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fn clone(&self) -> BinaryHeap<T>
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &BinaryHeap<T>)
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Performs copy-assignment from source. Read more
© 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/std/collections/struct.BinaryHeap.html