Function dfs 

pub fn dfs(graph: &Graph, root: VertexId) -> IgraphResult<Vec<VertexId>>

Pre-order visit of vertices reachable from root, in DFS order.

Vertices unreachable from root are not included. Errors if root is not a valid vertex. Neighbour iteration follows Graph::neighbors’s order, which matches python-igraph’s Graph.dfs and the upstream igraph_dfs order.

Examples

use rust_igraph::{Graph, dfs};

// 0 - 1 - 3
// |
// 2
let mut g = Graph::with_vertices(4);
g.add_edge(0, 1).unwrap();
g.add_edge(0, 2).unwrap();
g.add_edge(1, 3).unwrap();

let order = dfs(&g, 0).unwrap();
assert_eq!(order[0], 0);                // always start at root
assert_eq!(order.len(), 4);              // visits whole component