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use crate::algo::graph::tree::center::{Center, TreeCenter};
use crate::algo::graph::tree::rooting::TreeNode;
use crate::algo::graph::UnweightedAdjacencyList;
impl From<Center> for Vec<usize> {
fn from(center: Center) -> Self {
match center {
Center::One(x) => vec![x],
Center::Two(x, y) => vec![x, y],
}
}
}
impl TreeNode {
pub fn encode(&self) -> Vec<u8> {
let mut labels: Vec<_> = self.children.iter().map(|node| node.encode()).collect();
labels.sort();
let mut res = Vec::new();
res.push(b'(');
for label in &labels {
res.extend_from_slice(label);
}
res.push(b')');
res
}
}
impl UnweightedAdjacencyList {
pub fn is_isomorphic_with(&self, other: &UnweightedAdjacencyList) -> bool {
let this_centers: Vec<usize> = self.center().into();
let other_centers: Vec<usize> = other.center().into();
for &c1 in &this_centers {
let tree1 = TreeNode::from_adjacency_list(&self, c1);
for &c2 in &other_centers {
let tree2 = TreeNode::from_adjacency_list(&self, c2);
if tree1.encode() == tree2.encode() {
return true;
}
}
}
false
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_tree_encoding() {
let adj = UnweightedAdjacencyList::new_undirected(
10,
&[
[0, 2],
[0, 1],
[0, 3],
[2, 6],
[2, 7],
[1, 4],
[1, 5],
[5, 9],
[3, 8],
],
);
let tree = TreeNode::from_adjacency_list(&adj, 0);
let encoded = tree.encode();
let encoded = String::from_utf8(encoded).unwrap();
assert_eq!(&encoded, "(((())())(()())(()))")
}
#[test]
fn test_tree_isomorphism() {
let tree1 = UnweightedAdjacencyList::new_undirected(5, &[[2, 0], [3, 4], [2, 1], [2, 3]]);
let tree2 = UnweightedAdjacencyList::new_undirected(5, &[[1, 0], [2, 4], [1, 3], [1, 2]]);
assert!(tree1.is_isomorphic_with(&tree2));
}
}