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