Function greedy_clique_number 

pub fn greedy_clique_number(graph: &Graph) -> IgraphResult<u32>

Compute the greedy clique number (lower bound on chromatic number).

Uses a greedy approach: iteratively pick an uncoloured vertex with the most uncoloured neighbours and add it to a clique if it’s adjacent to all current clique members. This gives ω(G) ≤ χ(G).

Examples

use rust_igraph::{Graph, greedy_clique_number};

// K_4: clique number is 4
let g = Graph::from_edges(
    &[(0,1),(0,2),(0,3),(1,2),(1,3),(2,3)], false, Some(4)
).unwrap();
assert_eq!(greedy_clique_number(&g).unwrap(), 4);