## pathfinding

Pathfinding, flow, and graph algorithms

### 78 releases (24 stable)

✓ Uses Rust 2018 edition

 2.0.4 Feb 8, 2020 Dec 18, 2019 Oct 21, 2019 Feb 4, 2019 Dec 30, 2016

#6 in Algorithms

Used in 4 crates

Apache-2.0/MIT

130KB
2.5K SLoC

# pathfinding

This crate implements several pathfinding, flow, and graph algorithms in Rust.

## Algorithms

The algorithms are generic over their arguments.

### Directed graphs

• A*: find the shortest path in a weighted graph using an heuristic to guide the process.
• BFS: explore nearest successors first, then widen the search.
• DFS: explore a graph by going as far as possible, then backtrack.
• Dijkstra: find the shortest path in a weighted graph.
• Edmonds Karp: find the maximum flow in a weighted graph.
• Fringe: find the shortest path in a weighted graph using an heuristic to guide the process.
• IDA*: explore longer and longer paths in a weighted graph at the cost of multiple similar examinations.
• IDDFS: explore longer and longer paths in an unweighted graph at the cost of multiple similar examinations.
• strongly connected components: find strongly connected components in a directed graph.
• topological sorting: find an acceptable topological order in a directed graph.

### Matching

• Kuhn-Munkres (Hungarian algorithm): find the maximum (or minimum) matching in a weighted bipartite graph.

## Using this crate

In your `Cargo.toml`, put:

``````[dependencies]
pathfinding = "2.0.4"
``````

You can then pull your preferred algorithm (BFS in this example) using:

``````extern crate pathfinding;

use pathfinding::prelude::bfs;
``````

## Example

We will search the shortest path on a chess board to go from (1, 1) to (4, 6) doing only knight moves.

``````use pathfinding::prelude::bfs;

#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
struct Pos(i32, i32);

impl Pos {
fn successors(&self) -> Vec<Pos> {
let &Pos(x, y) = self;
vec![Pos(x+1,y+2), Pos(x+1,y-2), Pos(x-1,y+2), Pos(x-1,y-2),
Pos(x+2,y+1), Pos(x+2,y-1), Pos(x-2,y+1), Pos(x-2,y-1)]
}
}

static GOAL: Pos = Pos(4, 6);
let result = bfs(&Pos(1, 1), |p| p.successors(), |p| *p == GOAL);
assert_eq!(result.expect("no path found").len(), 5);
``````

This code is released under a dual Apache 2.0 / MIT free software license.

## Contributing

You are welcome to contribute by opening issues or submitting pull requests. Please open an issue before implementing a new feature, in case it is a work in progress already or it is fit for this repository.

In order to pass the continuous integration tests, your code must be formatted using the latest `rustfmt` with the nightly rust toolchain (available as the `rustfmt-preview` component of `rustup`).

This repository use the imperative mode in commit messages, such as "Add IDDFS", "Fix #xxx". This style is preferred over "Added IDDFS" or "Fixed #xxx".

~605KB
~12K SLoC