/// make undirected edges to bidirected.
pub fn edges_to_bidirected(edges: &[(usize, usize)]) -> Vec<(usize, usize)> {
edges
.to_vec()
.into_iter()
.chain(edges.to_vec().into_iter().map(|(u, v)| (v, u)))
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
assert_eq!(edges_to_bidirected(&vec![(0, 1)]), vec![(0, 1), (1, 0)]);
}
}