#[derive(Debug, Clone)]
pub struct UnionFind {
parent: Vec<usize>,
rank: Vec<u8>,
}
impl UnionFind {
pub fn new(size: usize) -> Self {
Self {
parent: (0..size).collect(),
rank: vec![0; size],
}
}
pub fn find(&mut self, x: usize) -> usize {
if self.parent[x] != x {
let root = self.find(self.parent[x]);
self.parent[x] = root;
}
self.parent[x]
}
pub fn union(&mut self, a: usize, b: usize) -> bool {
let ra = self.find(a);
let rb = self.find(b);
if ra == rb {
return false;
}
match self.rank[ra].cmp(&self.rank[rb]) {
std::cmp::Ordering::Less => self.parent[ra] = rb,
std::cmp::Ordering::Greater => self.parent[rb] = ra,
std::cmp::Ordering::Equal => {
self.parent[rb] = ra;
self.rank[ra] += 1;
}
}
true
}
}