# Struct petgraph::visit::Bfs [−] [src]

```pub struct Bfs<N, VM> {
pub stack: VecDeque<N>,
pub discovered: VM,
}```

A breadth first search (BFS) of a graph.

Using a Bfs you can run a traversal over a graph while still retaining mutable access to it, if you use it like the following example:

```use petgraph::{Graph, Bfs};

let mut graph = Graph::<_,()>::new();

let mut bfs = Bfs::new(&graph, a);
while let Some(nx) = bfs.next(&graph) {
// we can access `graph` mutably here still
graph[nx] += 1;
}

assert_eq!(graph[a], 1);```

Note: The algorithm may not behave correctly if nodes are removed during iteration. It may not necessarily visit added nodes or edges.

## Fields

`stack: VecDeque<N>`

The queue of nodes to visit

`discovered: VM`

The map of discovered nodes

## Methods

### `impl<N, VM> Bfs<N, VM> where N: Clone, VM: VisitMap<N>`[src]

#### `fn new<G>(graph: &G, start: N) -> Self where G: Visitable<NodeId=N, Map=VM>`

Create a new Bfs, using the graph's visitor map, and put start in the stack of nodes to visit.

#### `fn next<'a, G>(&mut self, graph: &'a G) -> Option<N> where G: Graphlike<NodeId=N>, G: NeighborIter<'a>`

Return the next node in the dfs, or None if the traversal is done.

## Trait Implementations

### `impl<N: Clone, VM: Clone> Clone for Bfs<N, VM>`[src]

#### `fn clone(&self) -> Bfs<N, VM>`

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0

Performs copy-assignment from `source`. Read more