886 lines
26 KiB
Rust
886 lines
26 KiB
Rust
// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A priority queue implemented with a binary heap.
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//!
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//! Insertion and popping the largest element have `O(log n)` time complexity. Checking the largest
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//! element is `O(1)`. Converting a vector to a binary heap can be done in-place, and has `O(n)`
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//! complexity. A binary heap can also be converted to a sorted vector in-place, allowing it to
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//! be used for an `O(n log n)` in-place heapsort.
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//!
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//! # Examples
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//!
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//! This is a larger example that implements [Dijkstra's algorithm][dijkstra]
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//! to solve the [shortest path problem][sssp] on a [directed graph][dir_graph].
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//! It shows how to use `BinaryHeap` with custom types.
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//!
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//! [dijkstra]: http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm
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//! [sssp]: http://en.wikipedia.org/wiki/Shortest_path_problem
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//! [dir_graph]: http://en.wikipedia.org/wiki/Directed_graph
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//!
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//! ```
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//! use std::cmp::Ordering;
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//! use std::collections::BinaryHeap;
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//! use std::uint;
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//!
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//! #[derive(Copy, Eq, PartialEq)]
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//! struct State {
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//! cost: uint,
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//! position: uint,
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//! }
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//!
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//! // The priority queue depends on `Ord`.
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//! // Explicitly implement the trait so the queue becomes a min-heap
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//! // instead of a max-heap.
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//! impl Ord for State {
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//! fn cmp(&self, other: &State) -> Ordering {
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//! // Notice that the we flip the ordering here
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//! other.cost.cmp(&self.cost)
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//! }
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//! }
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//!
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//! // `PartialOrd` needs to be implemented as well.
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//! impl PartialOrd for State {
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//! fn partial_cmp(&self, other: &State) -> Option<Ordering> {
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//! Some(self.cmp(other))
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//! }
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//! }
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//!
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//! // Each node is represented as an `uint`, for a shorter implementation.
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//! struct Edge {
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//! node: uint,
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//! cost: uint,
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//! }
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//!
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//! // Dijkstra's shortest path algorithm.
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//!
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//! // Start at `start` and use `dist` to track the current shortest distance
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//! // to each node. This implementation isn't memory-efficient as it may leave duplicate
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//! // nodes in the queue. It also uses `uint::MAX` as a sentinel value,
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//! // for a simpler implementation.
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//! fn shortest_path(adj_list: &Vec<Vec<Edge>>, start: uint, goal: uint) -> uint {
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//! // dist[node] = current shortest distance from `start` to `node`
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//! let mut dist: Vec<_> = (0..adj_list.len()).map(|_| uint::MAX).collect();
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//!
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//! let mut heap = BinaryHeap::new();
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//!
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//! // We're at `start`, with a zero cost
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//! dist[start] = 0;
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//! heap.push(State { cost: 0, position: start });
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//!
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//! // Examine the frontier with lower cost nodes first (min-heap)
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//! while let Some(State { cost, position }) = heap.pop() {
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//! // Alternatively we could have continued to find all shortest paths
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//! if position == goal { return cost; }
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//!
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//! // Important as we may have already found a better way
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//! if cost > dist[position] { continue; }
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//!
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//! // For each node we can reach, see if we can find a way with
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//! // a lower cost going through this node
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//! for edge in adj_list[position].iter() {
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//! let next = State { cost: cost + edge.cost, position: edge.node };
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//!
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//! // If so, add it to the frontier and continue
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//! if next.cost < dist[next.position] {
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//! heap.push(next);
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//! // Relaxation, we have now found a better way
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//! dist[next.position] = next.cost;
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//! }
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//! }
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//! }
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//!
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//! // Goal not reachable
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//! uint::MAX
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//! }
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//!
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//! fn main() {
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//! // This is the directed graph we're going to use.
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//! // The node numbers correspond to the different states,
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//! // and the edge weights symbolize the cost of moving
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//! // from one node to another.
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//! // Note that the edges are one-way.
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//! //
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//! // 7
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//! // +-----------------+
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//! // | |
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//! // v 1 2 |
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//! // 0 -----> 1 -----> 3 ---> 4
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//! // | ^ ^ ^
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//! // | | 1 | |
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//! // | | | 3 | 1
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//! // +------> 2 -------+ |
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//! // 10 | |
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//! // +---------------+
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//! //
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//! // The graph is represented as an adjacency list where each index,
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//! // corresponding to a node value, has a list of outgoing edges.
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//! // Chosen for its efficiency.
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//! let graph = vec![
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//! // Node 0
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//! vec![Edge { node: 2, cost: 10 },
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//! Edge { node: 1, cost: 1 }],
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//! // Node 1
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//! vec![Edge { node: 3, cost: 2 }],
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//! // Node 2
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//! vec![Edge { node: 1, cost: 1 },
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//! Edge { node: 3, cost: 3 },
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//! Edge { node: 4, cost: 1 }],
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//! // Node 3
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//! vec![Edge { node: 0, cost: 7 },
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//! Edge { node: 4, cost: 2 }],
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//! // Node 4
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//! vec![]];
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//!
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//! assert_eq!(shortest_path(&graph, 0, 1), 1);
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//! assert_eq!(shortest_path(&graph, 0, 3), 3);
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//! assert_eq!(shortest_path(&graph, 3, 0), 7);
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//! assert_eq!(shortest_path(&graph, 0, 4), 5);
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//! assert_eq!(shortest_path(&graph, 4, 0), uint::MAX);
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//! }
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//! ```
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#![allow(missing_docs)]
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#![stable(feature = "rust1", since = "1.0.0")]
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use core::prelude::*;
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use core::default::Default;
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use core::iter::FromIterator;
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use core::mem::{zeroed, replace, swap};
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use core::ptr;
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use slice;
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use vec::{self, Vec};
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/// A priority queue implemented with a binary heap.
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///
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/// This will be a max-heap.
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#[derive(Clone)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct BinaryHeap<T> {
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data: Vec<T>,
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<T: Ord> Default for BinaryHeap<T> {
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#[inline]
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fn default() -> BinaryHeap<T> { BinaryHeap::new() }
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}
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impl<T: Ord> BinaryHeap<T> {
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/// Creates an empty `BinaryHeap` as a max-heap.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// heap.push(4u);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> BinaryHeap<T> { BinaryHeap { data: vec![] } }
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/// Creates an empty `BinaryHeap` with a specific capacity.
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/// This preallocates enough memory for `capacity` elements,
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/// so that the `BinaryHeap` does not have to be reallocated
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/// until it contains at least that many values.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::with_capacity(10);
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/// heap.push(4u);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn with_capacity(capacity: uint) -> BinaryHeap<T> {
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BinaryHeap { data: Vec::with_capacity(capacity) }
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}
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/// Creates a `BinaryHeap` from a vector. This is sometimes called
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/// `heapifying` the vector.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let heap = BinaryHeap::from_vec(vec![9, 1, 2, 7, 3, 2]);
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/// ```
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pub fn from_vec(vec: Vec<T>) -> BinaryHeap<T> {
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let mut heap = BinaryHeap { data: vec };
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let mut n = heap.len() / 2;
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while n > 0 {
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n -= 1;
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heap.sift_down(n);
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}
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heap
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}
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/// Returns an iterator visiting all values in the underlying vector, in
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/// arbitrary order.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let heap = BinaryHeap::from_vec(vec![1, 2, 3, 4]);
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///
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/// // Print 1, 2, 3, 4 in arbitrary order
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/// for x in heap.iter() {
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/// println!("{}", x);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn iter(&self) -> Iter<T> {
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Iter { iter: self.data.iter() }
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}
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/// Creates a consuming iterator, that is, one that moves each value out of
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/// the binary heap in arbitrary order. The binary heap cannot be used
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/// after calling this.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let heap = BinaryHeap::from_vec(vec![1, 2, 3, 4]);
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///
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/// // Print 1, 2, 3, 4 in arbitrary order
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/// for x in heap.into_iter() {
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/// // x has type int, not &int
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/// println!("{}", x);
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn into_iter(self) -> IntoIter<T> {
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IntoIter { iter: self.data.into_iter() }
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}
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/// Returns the greatest item in the binary heap, or `None` if it is empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// assert_eq!(heap.peek(), None);
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///
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/// heap.push(1);
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/// heap.push(5);
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/// heap.push(2);
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/// assert_eq!(heap.peek(), Some(&5));
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///
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn peek(&self) -> Option<&T> {
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self.data.get(0)
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}
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/// Returns the number of elements the binary heap can hold without reallocating.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::with_capacity(100);
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/// assert!(heap.capacity() >= 100);
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/// heap.push(4u);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn capacity(&self) -> uint { self.data.capacity() }
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/// Reserves the minimum capacity for exactly `additional` more elements to be inserted in the
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/// given `BinaryHeap`. Does nothing if the capacity is already sufficient.
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///
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/// Note that the allocator may give the collection more space than it requests. Therefore
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/// capacity can not be relied upon to be precisely minimal. Prefer `reserve` if future
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/// insertions are expected.
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///
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/// # Panics
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///
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/// Panics if the new capacity overflows `uint`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// heap.reserve_exact(100);
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/// assert!(heap.capacity() >= 100);
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/// heap.push(4u);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn reserve_exact(&mut self, additional: uint) {
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self.data.reserve_exact(additional);
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}
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/// Reserves capacity for at least `additional` more elements to be inserted in the
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/// `BinaryHeap`. The collection may reserve more space to avoid frequent reallocations.
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///
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/// # Panics
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///
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/// Panics if the new capacity overflows `uint`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// heap.reserve(100);
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/// assert!(heap.capacity() >= 100);
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/// heap.push(4u);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn reserve(&mut self, additional: uint) {
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self.data.reserve(additional);
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}
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/// Discards as much additional capacity as possible.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn shrink_to_fit(&mut self) {
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self.data.shrink_to_fit();
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}
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/// Removes the greatest item from the binary heap and returns it, or `None` if it
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/// is empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::from_vec(vec![1, 3]);
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///
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/// assert_eq!(heap.pop(), Some(3));
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/// assert_eq!(heap.pop(), Some(1));
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/// assert_eq!(heap.pop(), None);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn pop(&mut self) -> Option<T> {
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self.data.pop().map(|mut item| {
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if !self.is_empty() {
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swap(&mut item, &mut self.data[0]);
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self.sift_down(0);
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}
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item
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})
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}
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/// Pushes an item onto the binary heap.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// heap.push(3);
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/// heap.push(5);
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/// heap.push(1);
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///
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/// assert_eq!(heap.len(), 3);
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/// assert_eq!(heap.peek(), Some(&5));
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn push(&mut self, item: T) {
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let old_len = self.len();
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self.data.push(item);
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self.sift_up(0, old_len);
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}
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/// Pushes an item onto the binary heap, then pops the greatest item off the queue in
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/// an optimized fashion.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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/// heap.push(1);
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/// heap.push(5);
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///
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/// assert_eq!(heap.push_pop(3), 5);
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/// assert_eq!(heap.push_pop(9), 9);
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/// assert_eq!(heap.len(), 2);
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/// assert_eq!(heap.peek(), Some(&3));
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/// ```
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pub fn push_pop(&mut self, mut item: T) -> T {
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match self.data.get_mut(0) {
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None => return item,
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Some(top) => if *top > item {
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swap(&mut item, top);
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} else {
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return item;
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},
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}
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self.sift_down(0);
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item
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}
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/// Pops the greatest item off the binary heap, then pushes an item onto the queue in
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/// an optimized fashion. The push is done regardless of whether the binary heap
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/// was empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let mut heap = BinaryHeap::new();
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///
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/// assert_eq!(heap.replace(1), None);
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/// assert_eq!(heap.replace(3), Some(1));
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/// assert_eq!(heap.len(), 1);
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/// assert_eq!(heap.peek(), Some(&3));
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/// ```
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pub fn replace(&mut self, mut item: T) -> Option<T> {
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if !self.is_empty() {
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swap(&mut item, &mut self.data[0]);
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self.sift_down(0);
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Some(item)
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} else {
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self.push(item);
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None
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}
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}
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/// Consumes the `BinaryHeap` and returns the underlying vector
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/// in arbitrary order.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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/// let heap = BinaryHeap::from_vec(vec![1, 2, 3, 4, 5, 6, 7]);
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/// let vec = heap.into_vec();
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///
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/// // Will print in some order
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/// for x in vec.iter() {
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/// println!("{}", x);
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/// }
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/// ```
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pub fn into_vec(self) -> Vec<T> { self.data }
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/// Consumes the `BinaryHeap` and returns a vector in sorted
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/// (ascending) order.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::BinaryHeap;
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///
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/// let mut heap = BinaryHeap::from_vec(vec![1, 2, 4, 5, 7]);
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/// heap.push(6);
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/// heap.push(3);
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///
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/// let vec = heap.into_sorted_vec();
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/// assert_eq!(vec, vec![1, 2, 3, 4, 5, 6, 7]);
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/// ```
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pub fn into_sorted_vec(mut self) -> Vec<T> {
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let mut end = self.len();
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while end > 1 {
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end -= 1;
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self.data.swap(0, end);
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self.sift_down_range(0, end);
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}
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self.into_vec()
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}
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// The implementations of sift_up and sift_down use unsafe blocks in
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// order to move an element out of the vector (leaving behind a
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// zeroed element), shift along the others and move it back into the
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// vector over the junk element. This reduces the constant factor
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// compared to using swaps, which involves twice as many moves.
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fn sift_up(&mut self, start: uint, mut pos: uint) {
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unsafe {
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let new = replace(&mut self.data[pos], zeroed());
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while pos > start {
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let parent = (pos - 1) >> 1;
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if new <= self.data[parent] { break; }
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|
|
let x = replace(&mut self.data[parent], zeroed());
|
|
ptr::write(&mut self.data[pos], x);
|
|
pos = parent;
|
|
}
|
|
ptr::write(&mut self.data[pos], new);
|
|
}
|
|
}
|
|
|
|
fn sift_down_range(&mut self, mut pos: uint, end: uint) {
|
|
unsafe {
|
|
let start = pos;
|
|
let new = replace(&mut self.data[pos], zeroed());
|
|
|
|
let mut child = 2 * pos + 1;
|
|
while child < end {
|
|
let right = child + 1;
|
|
if right < end && !(self.data[child] > self.data[right]) {
|
|
child = right;
|
|
}
|
|
let x = replace(&mut self.data[child], zeroed());
|
|
ptr::write(&mut self.data[pos], x);
|
|
pos = child;
|
|
child = 2 * pos + 1;
|
|
}
|
|
|
|
ptr::write(&mut self.data[pos], new);
|
|
self.sift_up(start, pos);
|
|
}
|
|
}
|
|
|
|
fn sift_down(&mut self, pos: uint) {
|
|
let len = self.len();
|
|
self.sift_down_range(pos, len);
|
|
}
|
|
|
|
/// Returns the length of the binary heap.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn len(&self) -> uint { self.data.len() }
|
|
|
|
/// Checks if the binary heap is empty.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_empty(&self) -> bool { self.len() == 0 }
|
|
|
|
/// Clears the binary heap, returning an iterator over the removed elements.
|
|
#[inline]
|
|
#[unstable(feature = "collections",
|
|
reason = "matches collection reform specification, waiting for dust to settle")]
|
|
pub fn drain(&mut self) -> Drain<T> {
|
|
Drain { iter: self.data.drain() }
|
|
}
|
|
|
|
/// Drops all items from the binary heap.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn clear(&mut self) { self.drain(); }
|
|
}
|
|
|
|
/// `BinaryHeap` iterator.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Iter <'a, T: 'a> {
|
|
iter: slice::Iter<'a, T>,
|
|
}
|
|
|
|
// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Clone for Iter<'a, T> {
|
|
fn clone(&self) -> Iter<'a, T> {
|
|
Iter { iter: self.iter.clone() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Iterator for Iter<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a T> { self.iter.next() }
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<&'a T> { self.iter.next_back() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
|
|
|
|
/// An iterator that moves out of a `BinaryHeap`.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct IntoIter<T> {
|
|
iter: vec::IntoIter<T>,
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Iterator for IntoIter<T> {
|
|
type Item = T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<T> { self.iter.next() }
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> DoubleEndedIterator for IntoIter<T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> ExactSizeIterator for IntoIter<T> {}
|
|
|
|
/// An iterator that drains a `BinaryHeap`.
|
|
#[unstable(feature = "collections", reason = "recent addition")]
|
|
pub struct Drain<'a, T: 'a> {
|
|
iter: vec::Drain<'a, T>,
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: 'a> Iterator for Drain<'a, T> {
|
|
type Item = T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<T> { self.iter.next() }
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> FromIterator<T> for BinaryHeap<T> {
|
|
fn from_iter<Iter: Iterator<Item=T>>(iter: Iter) -> BinaryHeap<T> {
|
|
BinaryHeap::from_vec(iter.collect())
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> Extend<T> for BinaryHeap<T> {
|
|
fn extend<Iter: Iterator<Item=T>>(&mut self, mut iter: Iter) {
|
|
let (lower, _) = iter.size_hint();
|
|
|
|
self.reserve(lower);
|
|
|
|
for elem in iter {
|
|
self.push(elem);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use prelude::*;
|
|
|
|
use super::BinaryHeap;
|
|
|
|
#[test]
|
|
fn test_iterator() {
|
|
let data = vec!(5, 9, 3);
|
|
let iterout = [9, 5, 3];
|
|
let heap = BinaryHeap::from_vec(data);
|
|
let mut i = 0;
|
|
for el in heap.iter() {
|
|
assert_eq!(*el, iterout[i]);
|
|
i += 1;
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_reverse() {
|
|
let data = vec!(5, 9, 3);
|
|
let iterout = vec!(3, 5, 9);
|
|
let pq = BinaryHeap::from_vec(data);
|
|
|
|
let v: Vec<int> = pq.iter().rev().map(|&x| x).collect();
|
|
assert_eq!(v, iterout);
|
|
}
|
|
|
|
#[test]
|
|
fn test_move_iter() {
|
|
let data = vec!(5, 9, 3);
|
|
let iterout = vec!(9, 5, 3);
|
|
let pq = BinaryHeap::from_vec(data);
|
|
|
|
let v: Vec<int> = pq.into_iter().collect();
|
|
assert_eq!(v, iterout);
|
|
}
|
|
|
|
#[test]
|
|
fn test_move_iter_size_hint() {
|
|
let data = vec!(5, 9);
|
|
let pq = BinaryHeap::from_vec(data);
|
|
|
|
let mut it = pq.into_iter();
|
|
|
|
assert_eq!(it.size_hint(), (2, Some(2)));
|
|
assert_eq!(it.next(), Some(9));
|
|
|
|
assert_eq!(it.size_hint(), (1, Some(1)));
|
|
assert_eq!(it.next(), Some(5));
|
|
|
|
assert_eq!(it.size_hint(), (0, Some(0)));
|
|
assert_eq!(it.next(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_move_iter_reverse() {
|
|
let data = vec!(5, 9, 3);
|
|
let iterout = vec!(3, 5, 9);
|
|
let pq = BinaryHeap::from_vec(data);
|
|
|
|
let v: Vec<int> = pq.into_iter().rev().collect();
|
|
assert_eq!(v, iterout);
|
|
}
|
|
|
|
#[test]
|
|
fn test_peek_and_pop() {
|
|
let data = vec!(2u, 4, 6, 2, 1, 8, 10, 3, 5, 7, 0, 9, 1);
|
|
let mut sorted = data.clone();
|
|
sorted.sort();
|
|
let mut heap = BinaryHeap::from_vec(data);
|
|
while !heap.is_empty() {
|
|
assert_eq!(heap.peek().unwrap(), sorted.last().unwrap());
|
|
assert_eq!(heap.pop().unwrap(), sorted.pop().unwrap());
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_push() {
|
|
let mut heap = BinaryHeap::from_vec(vec!(2, 4, 9));
|
|
assert_eq!(heap.len(), 3);
|
|
assert!(*heap.peek().unwrap() == 9);
|
|
heap.push(11);
|
|
assert_eq!(heap.len(), 4);
|
|
assert!(*heap.peek().unwrap() == 11);
|
|
heap.push(5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert!(*heap.peek().unwrap() == 11);
|
|
heap.push(27);
|
|
assert_eq!(heap.len(), 6);
|
|
assert!(*heap.peek().unwrap() == 27);
|
|
heap.push(3);
|
|
assert_eq!(heap.len(), 7);
|
|
assert!(*heap.peek().unwrap() == 27);
|
|
heap.push(103);
|
|
assert_eq!(heap.len(), 8);
|
|
assert!(*heap.peek().unwrap() == 103);
|
|
}
|
|
|
|
#[test]
|
|
fn test_push_unique() {
|
|
let mut heap = BinaryHeap::from_vec(vec!(box 2, box 4, box 9));
|
|
assert_eq!(heap.len(), 3);
|
|
assert!(*heap.peek().unwrap() == box 9);
|
|
heap.push(box 11);
|
|
assert_eq!(heap.len(), 4);
|
|
assert!(*heap.peek().unwrap() == box 11);
|
|
heap.push(box 5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert!(*heap.peek().unwrap() == box 11);
|
|
heap.push(box 27);
|
|
assert_eq!(heap.len(), 6);
|
|
assert!(*heap.peek().unwrap() == box 27);
|
|
heap.push(box 3);
|
|
assert_eq!(heap.len(), 7);
|
|
assert!(*heap.peek().unwrap() == box 27);
|
|
heap.push(box 103);
|
|
assert_eq!(heap.len(), 8);
|
|
assert!(*heap.peek().unwrap() == box 103);
|
|
}
|
|
|
|
#[test]
|
|
fn test_push_pop() {
|
|
let mut heap = BinaryHeap::from_vec(vec!(5, 5, 2, 1, 3));
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.push_pop(6), 6);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.push_pop(0), 5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.push_pop(4), 5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.push_pop(1), 4);
|
|
assert_eq!(heap.len(), 5);
|
|
}
|
|
|
|
#[test]
|
|
fn test_replace() {
|
|
let mut heap = BinaryHeap::from_vec(vec!(5, 5, 2, 1, 3));
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.replace(6).unwrap(), 5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.replace(0).unwrap(), 6);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.replace(4).unwrap(), 5);
|
|
assert_eq!(heap.len(), 5);
|
|
assert_eq!(heap.replace(1).unwrap(), 4);
|
|
assert_eq!(heap.len(), 5);
|
|
}
|
|
|
|
fn check_to_vec(mut data: Vec<int>) {
|
|
let heap = BinaryHeap::from_vec(data.clone());
|
|
let mut v = heap.clone().into_vec();
|
|
v.sort();
|
|
data.sort();
|
|
|
|
assert_eq!(v, data);
|
|
assert_eq!(heap.into_sorted_vec(), data);
|
|
}
|
|
|
|
#[test]
|
|
fn test_to_vec() {
|
|
check_to_vec(vec!());
|
|
check_to_vec(vec!(5));
|
|
check_to_vec(vec!(3, 2));
|
|
check_to_vec(vec!(2, 3));
|
|
check_to_vec(vec!(5, 1, 2));
|
|
check_to_vec(vec!(1, 100, 2, 3));
|
|
check_to_vec(vec!(1, 3, 5, 7, 9, 2, 4, 6, 8, 0));
|
|
check_to_vec(vec!(2, 4, 6, 2, 1, 8, 10, 3, 5, 7, 0, 9, 1));
|
|
check_to_vec(vec!(9, 11, 9, 9, 9, 9, 11, 2, 3, 4, 11, 9, 0, 0, 0, 0));
|
|
check_to_vec(vec!(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
|
|
check_to_vec(vec!(10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0));
|
|
check_to_vec(vec!(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 1, 2));
|
|
check_to_vec(vec!(5, 4, 3, 2, 1, 5, 4, 3, 2, 1, 5, 4, 3, 2, 1));
|
|
}
|
|
|
|
#[test]
|
|
fn test_empty_pop() {
|
|
let mut heap = BinaryHeap::<int>::new();
|
|
assert!(heap.pop().is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_empty_peek() {
|
|
let empty = BinaryHeap::<int>::new();
|
|
assert!(empty.peek().is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_empty_replace() {
|
|
let mut heap = BinaryHeap::<int>::new();
|
|
assert!(heap.replace(5).is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_from_iter() {
|
|
let xs = vec!(9u, 8, 7, 6, 5, 4, 3, 2, 1);
|
|
|
|
let mut q: BinaryHeap<uint> = xs.iter().rev().map(|&x| x).collect();
|
|
|
|
for &x in xs.iter() {
|
|
assert_eq!(q.pop().unwrap(), x);
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_drain() {
|
|
let mut q: BinaryHeap<_> =
|
|
[9u, 8, 7, 6, 5, 4, 3, 2, 1].iter().cloned().collect();
|
|
|
|
assert_eq!(q.drain().take(5).count(), 5);
|
|
|
|
assert!(q.is_empty());
|
|
}
|
|
}
|