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use std::collections::HashMap;
use std::hash::Hash;
use std::rc::Rc;
#[derive(Clone)]
enum SetItem<ValueType> {
Root(ValueType, u32),
Link(Box<SetItem<ValueType>>)
}
pub struct DisjointSet<T: Clone>
{
set_size: usize,
parent: Vec<usize>,
map: HashMap<T, usize>
}
impl<T> DisjointSet<T> where T: Clone+Hash+Eq
{
pub fn new() -> Self{
DisjointSet{
set_size: 0,
parent: Vec::new(),
map: HashMap::new()
}
}
pub fn make_set(&mut self, x: T){
let mut len = &mut self.set_size;
match self.map.get(&x) {
Some(p) => return,
None => {}
}
self.map.insert(x, *len);
self.parent.push(*len);
*len += 1;
}
pub fn find(&mut self, x: T) -> Option<usize>
{
let mut pos: usize;
match self.map.get(&x) {
Some(p) => {pos = *p;},
None => return None
}
let ret = DisjointSet::<T>::find_internal(&mut self.parent, pos);
Some(ret)
}
fn find_internal(p: &mut Vec<usize>, n: usize) -> usize{
if p[n] != n{
let parent = p[n];
p[n] = DisjointSet::<T>::find_internal(p, parent);
p[n]
}
else {
n
}
}
pub fn union(&mut self, x: T, y: T) -> Result<usize, ()>
{
let x_root;
let y_root;
match self.find(x) {
Some(x_r) => {x_root = x_r;} ,
None => {return Err(());}
}
match self.find(y) {
Some(y_r) => {y_root = y_r;} ,
None => {return Err(());}
}
self.parent[x_root] = y_root;
Ok(y_root)
}
}
#[test]
fn it_works() {
let mut ds = DisjointSet::<i32>::new();
ds.make_set(1);
ds.make_set(2);
ds.make_set(3);
assert!(ds.find(1) != ds.find(2));
assert!(ds.find(2) != ds.find(3));
ds.union(1, 2);
ds.union(2, 3);
assert!(ds.find(1) == ds.find(3));
assert!(ds.find(4) == None);
ds.make_set(4);
assert!(ds.find(4) != None);
ds.make_set(-1);
assert!(ds.find(-1) != ds.find(3));
ds.union(-1, 4);
ds.union(2, 4);
assert!(ds.find(-1) == ds.find(3));
}