Struct std::collections::BinaryHeap
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pub struct BinaryHeap<T> {
// some 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.
Methods
impl<T> BinaryHeap<T> where T: Ord
fn new() -> BinaryHeap<T>
Creates an empty BinaryHeap as a max-heap.
Examples
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
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 from_vec(vec: Vec<T>) -> BinaryHeap<T>
: use BinaryHeap::from instead
Creates a BinaryHeap from a vector. This is sometimes called
heapifying the vector.
Examples
#![feature(binary_heap_extras)] fn main() { #![allow(deprecated)] use std::collections::BinaryHeap; let heap = BinaryHeap::from_vec(vec![9, 1, 2, 7, 3, 2]); }#![feature(binary_heap_extras)] use std::collections::BinaryHeap; let heap = BinaryHeap::from_vec(vec![9, 1, 2, 7, 3, 2]);
fn iter(&self) -> Iter<T>
Returns an iterator visiting all values in the underlying vector, in arbitrary order.
Examples
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
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
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
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
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
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
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
Pushes an item onto the binary heap, then pops the greatest item off the queue in an optimized fashion.
Examples
#![feature(binary_heap_extras)] 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>
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)] 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
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
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 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.