Function is_outerplanar 

pub fn is_outerplanar(graph: &Graph) -> IgraphResult<bool>

Check whether a graph is outerplanar.

Uses the characterization: outerplanar iff no K_4 minor (series-parallel) and no K_{2,3} minor.

Directed graphs are treated as undirected.

Examples

use rust_igraph::{Graph, is_outerplanar};

// Cycle C_5: outerplanar
let mut g = Graph::with_vertices(5);
g.add_edge(0, 1).unwrap();
g.add_edge(1, 2).unwrap();
g.add_edge(2, 3).unwrap();
g.add_edge(3, 4).unwrap();
g.add_edge(4, 0).unwrap();
assert!(is_outerplanar(&g).unwrap());

// K_4: NOT outerplanar (has K_4 minor)
let mut g = Graph::with_vertices(4);
for i in 0..4u32 {
    for j in (i+1)..4 {
        g.add_edge(i, j).unwrap();
    }
}
assert!(!is_outerplanar(&g).unwrap());