Function edge_chromatic_number 

pub fn edge_chromatic_number(colors: &[u32]) -> u32

Return the number of distinct colors used by an edge coloring.

Examples

use rust_igraph::{Graph, edge_coloring_greedy, edge_chromatic_number};

let mut g = Graph::with_vertices(3);
g.add_edge(0, 1).unwrap();
g.add_edge(1, 2).unwrap();
g.add_edge(2, 0).unwrap();
let colors = edge_coloring_greedy(&g).unwrap();
assert_eq!(edge_chromatic_number(&colors), 3);