Function rs_graph::search::path_from_incomings

pub fn path_from_incomings<N, E, I>(
    dst: N, 
    incomings: I
) -> impl Iterator<Item = E> where
    N: Copy,
    E: Clone,
    I: Fn(N) -> Option<(E, N)>, 

Compute a path from a map of incoming edges for each node.

Parameters

• dst: the destination node
• incomings(v): return the incoming edge and preceding node for node v (or None if it does not exist)

Return

An iterator over the incoming edges starting from the last one.

Example

// Breadth-first-search on a directed with 7 nodes.

use rs_graph::LinkedListGraph;
use rs_graph::traits::*;
use rs_graph::classes;
use rs_graph::search::{path_from_incomings, bfs};
use std::collections::{HashMap, VecDeque};

let g: LinkedListGraph = classes::cycle(7);

let mut incomings = HashMap::new();
let mut bfs = bfs::start_with_data(g.outgoing(), g.id2node(0), (&mut incomings, VecDeque::new()));
for _ in bfs {}

{
    let mut path = path_from_incomings(g.id2node(3), |u| incomings.get(&u).map(|&e| (e, g.src(e))));

    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(2));
    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(1));
    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(0));
    assert_eq!(path.next().map(|e| g.edge_id(e)), None);
}

{
    let mut path = path_from_incomings(g.id2node(4), |u| incomings.get(&u).map(|&e| (e, g.src(e))));

    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(3));
    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(2));
    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(1));
    assert_eq!(path.next().map(|e| g.edge_id(e)), Some(0));
    assert_eq!(path.next().map(|e| g.edge_id(e)), None);
}