https://github.com/lucidfrontier45/fpq
Priority Queue with scoring Function
https://github.com/lucidfrontier45/fpq
data-structures queue rust
Last synced: about 1 year ago
JSON representation
Priority Queue with scoring Function
- Host: GitHub
- URL: https://github.com/lucidfrontier45/fpq
- Owner: lucidfrontier45
- License: mit
- Created: 2023-10-23T22:40:56.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-03-12T12:33:36.000Z (about 1 year ago)
- Last Synced: 2025-03-12T12:45:12.985Z (about 1 year ago)
- Topics: data-structures, queue, rust
- Language: Rust
- Homepage: https://crates.io/crates/fpq
- Size: 8.79 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# FPQ
Priority Queue with scoring function
# Usage
- Rust Edition: 2024
- MSRV: 1.85
```toml
[dependencies]
fpq = "0.3.0"
```
In the code, you first need to create an instance with `fpq::PriorityQueue::new`. It takes a boxed closure that converts your item type `&T` into score type `S: Ord`. Then you can use `push/pop/peek` methods in the same way as `std::collections::BinaryHeap`.
# Example
```rust
use std::cmp::Reverse;
use fpq::PriorityQueue;
fn main() {
// a score function that returns the length of a string
let score_fn = Box::new(|s: &String| s.len());
// create a new priority queue with the score function
let mut queue = PriorityQueue::new(score_fn);
// the queue is empty at the beginning
assert!(queue.peek().is_none());
// push some items into the queue
// the score function is used to calculate the score of each item
queue.push("a".to_string()); // score = 1
queue.push("ccc".to_string()); // score = 3
queue.push("bb".to_string()); // score = 2
// you can also push an item with a explicit score
queue.push_with_score("b".to_string(), 10); // score = 10
// peek the item with the highest priority
assert_eq!(queue.peek(), Some((10, &"b".to_string())));
// pop the item with the highest priority
assert_eq!(queue.pop(), Some((10, "b".to_string())));
assert_eq!(queue.pop(), Some((3, "ccc".to_string())));
assert_eq!(queue.pop(), Some((2, "bb".to_string())));
assert_eq!(queue.pop(), Some((1, "a".to_string())));
// the queue is empty again
assert!(queue.peek().is_none());
// you can also use a reverse order
let score_fn = Box::new(|s: &String| Reverse(s.len()));
let mut queue = PriorityQueue::new(score_fn);
queue.push("a".to_string()); // score = -1
queue.push("ccc".to_string()); // score = -3
queue.push("bb".to_string()); // score = -2
// remember to use Reverse when pushing an item with an explicit score
queue.push_with_score("b".to_string(), Reverse(10)); // score = -10
assert_eq!(queue.peek(), Some((Reverse(1), &"a".to_string())));
assert_eq!(queue.pop(), Some((Reverse(1), "a".to_string())));
assert_eq!(queue.pop(), Some((Reverse(2), "bb".to_string())));
assert_eq!(queue.pop(), Some((Reverse(3), "ccc".to_string())));
assert_eq!(queue.pop(), Some((Reverse(10), "b".to_string())));
assert!(queue.peek().is_none());
}
```