https://github.com/lucidfrontier45/heapq

Priority Queue with scoring function
https://github.com/lucidfrontier45/heapq

data-structures queue rust

Last synced: about 4 hours ago
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Priority Queue with scoring function

• Host: GitHub
• URL: https://github.com/lucidfrontier45/heapq
• Owner: lucidfrontier45
• License: mit
• Created: 2023-10-23T22:40:56.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2023-10-24T01:45:29.000Z (about 1 year ago)
• Last Synced: 2024-04-24T19:02:22.224Z (7 months ago)
• Topics: data-structures, queue, rust
• Language: Rust
• Homepage: https://crates.io/crates/heapq
• Size: 5.86 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Heapq

Priority Queue with scoring function

# Usage

```toml

[dependencies]

heapq = "0.1.0"

```

In the code you first need to create an instance with `heaqp::PriorityQueue::new`. It takes a 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 heapq::PriorityQueue;

fn main() {

    // a score function that returns the length of a string

    let score_fn = |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(&"b".to_string()));

    // pop the item with the highest priority

    assert_eq!(queue.pop(), Some("b".to_string()));

    assert_eq!(queue.pop(), Some("ccc".to_string()));

    assert_eq!(queue.pop(), Some("bb".to_string()));

    assert_eq!(queue.pop(), Some("a".to_string()));

    // the queue is empty again

    assert!(queue.peek().is_none());

    // you can also use a reverse order

    let score_fn = |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 a explicit score

    queue.push_with_score("b".to_string(), Reverse(10)); // score = -10

    assert_eq!(queue.peek(), Some(&"a".to_string()));

    assert_eq!(queue.pop(), Some("a".to_string()));

    assert_eq!(queue.pop(), Some("bb".to_string()));

    assert_eq!(queue.pop(), Some("ccc".to_string()));

    assert_eq!(queue.pop(), Some("b".to_string()));

    assert!(queue.peek().is_none());

}

```