Struct collections::binary_heap::BinaryHeap [] [src]

pub struct BinaryHeap<T> {
    data: Vec<T>,
}

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.

Fields

data

Methods

impl<T: Ord> BinaryHeap<T>

fn new() -> BinaryHeap<T>

Creates an empty BinaryHeap as a max-heap.

Examples

extern crate collections; fn main() { use std::collections::BinaryHeap; let mut heap = BinaryHeap::new(); heap.push(4); }
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

extern crate collections; fn main() { use std::collections::BinaryHeap; let mut heap = BinaryHeap::with_capacity(10); heap.push(4); }
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

extern crate collections; fn main() { 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); } }
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

extern crate collections; fn main() { 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)); }
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 capacity(&self) -> usize

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

Examples

extern crate collections; fn main() { use std::collections::BinaryHeap; let mut heap = BinaryHeap::with_capacity(100); assert!(heap.capacity() >= 100); heap.push(4); }
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

extern crate collections; fn main() { use std::collections::BinaryHeap; let mut heap = BinaryHeap::new(); heap.reserve_exact(100); assert!(heap.capacity() >= 100); heap.push(4); }
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

extern crate collections; fn main() { use std::collections::BinaryHeap; let mut heap = BinaryHeap::new(); heap.reserve(100); assert!(heap.capacity() >= 100); heap.push(4); }
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.

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

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

Examples

extern crate collections; fn main() { 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); }
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

extern crate collections; fn main() { 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)); }
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

Unstable (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

#![feature(binary_heap_extras)] extern crate collections; fn main() { 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)); }
#![feature(binary_heap_extras)]

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>

Unstable (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

#![feature(binary_heap_extras)] extern crate collections; fn main() { 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)); }
#![feature(binary_heap_extras)]

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>

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

Examples

extern crate collections; fn main() { 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); } }
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.

Examples

extern crate collections; fn main() { 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]); }
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 sift_up(&mut self, start: usize, pos: usize)

fn sift_down_range(&mut self, pos: usize, end: usize)

Take an element at pos and move it down the heap, while its children are larger.

fn sift_down(&mut self, pos: usize)

fn sift_down_to_bottom(&mut self, pos: usize)

Take an element at pos and move it all the way down the heap, then sift it up to its position.

Note: This is faster when the element is known to be large / should be closer to the bottom.

fn len(&self) -> usize

Returns the length of the binary heap.

fn is_empty(&self) -> bool

Checks if the binary 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.

fn clear(&mut self)

Drops all items from the binary heap.

Trait Implementations

impl<T: Clone> Clone for BinaryHeap<T>

fn clone(&self) -> Self

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

impl<T: Ord> Default for BinaryHeap<T>

fn default() -> BinaryHeap<T>

impl<T: Debug + Ord> Debug for BinaryHeap<T>

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

impl<T: Ord> From<Vec<T>> for BinaryHeap<T>

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

impl<T: Ord> FromIterator<T> for BinaryHeap<T>

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

impl<T: Ord> IntoIterator for BinaryHeap<T>

type Item = T

type IntoIter = IntoIter<T>

fn into_iter(self) -> IntoIter<T>

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

type Item = &'a T

type IntoIter = Iter<'a, T>

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

impl<T: Ord> Extend<T> for BinaryHeap<T>

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

impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BinaryHeap<T>

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