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use std::cmp::Ordering; use std::fmt::Debug; use std::fmt::Formatter; use anyhow::Result; use binary_heap_plus::{BinaryHeap, FnComparator}; use crate::algorithms::{Queue, QueueType}; use crate::semirings::Semiring; use crate::StateId; #[derive(Clone)] pub struct StateWeightCompare<W: Semiring, C: Clone + Fn(&W, &W) -> Result<bool>> { less: C, weights: Vec<W>, } impl<W: Semiring, C: Clone + Fn(&W, &W) -> Result<bool>> StateWeightCompare<W, C> { pub fn new(weights: Vec<W>, less: C) -> Self { Self { less, weights } } pub fn compare(&self, s1: StateId, s2: StateId) -> Result<bool> { (self.less)(&self.weights[s1], &self.weights[s2]) } } pub fn natural_less<W: Semiring>(w1: &W, w2: &W) -> Result<bool> { Ok((&w1.plus(w2)? == w1) && (w1 != w2)) } #[derive(Clone)] pub struct ShortestFirstQueue<C: Clone + FnMut(&StateId, &StateId) -> Ordering> { heap: BinaryHeap<StateId, FnComparator<C>>, } impl<C: Clone + FnMut(&StateId, &StateId) -> Ordering> Debug for ShortestFirstQueue<C> { fn fmt(&self, f: &mut Formatter) -> std::fmt::Result { f.write_str(format!("ShortestFirstQueue {{ heap: {:?} }}", self.heap).as_str()) } } impl<C: Clone + FnMut(&StateId, &StateId) -> Ordering> ShortestFirstQueue<C> { pub fn new(c: C) -> Self { Self { heap: BinaryHeap::new_by(c), } } } impl<C: Clone + FnMut(&StateId, &StateId) -> Ordering> Queue for ShortestFirstQueue<C> { fn head(&mut self) -> Option<usize> { self.heap.peek().cloned() } fn enqueue(&mut self, state: usize) { self.heap.push(state); } fn dequeue(&mut self) { self.heap.pop(); } fn update(&mut self, _state: usize) { unimplemented!() } fn is_empty(&self) -> bool { self.heap.is_empty() } fn clear(&mut self) { self.heap.clear() } fn queue_type(&self) -> QueueType { QueueType::ShortestFirstQueue } } #[derive(Debug)] pub struct NaturalShortestFirstQueue { queue: Box<dyn Queue>, } impl NaturalShortestFirstQueue { pub fn new<W: 'static + Semiring>(weights: Vec<W>) -> Self { let a = StateWeightCompare::new(weights, natural_less); let heap = ShortestFirstQueue::new(move |v1, v2| { if a.compare(*v1, *v2).unwrap() { Ordering::Less } else { Ordering::Greater } }); NaturalShortestFirstQueue { queue: Box::new(heap), } } } impl Queue for NaturalShortestFirstQueue { fn head(&mut self) -> Option<usize> { self.queue.head() } fn enqueue(&mut self, state: usize) { self.queue.enqueue(state) } fn dequeue(&mut self) { self.queue.dequeue() } fn update(&mut self, state: usize) { self.queue.update(state) } fn is_empty(&self) -> bool { self.queue.is_empty() } fn clear(&mut self) { self.queue.clear() } fn queue_type(&self) -> QueueType { self.queue.queue_type() } }