struct Solution;
struct UnionFind {
parent: Vec<usize>,
n: usize,
}
impl UnionFind {
fn new(n: usize) -> Self {
let parent = (0..n).collect();
UnionFind { parent, n }
}
fn find(&mut self, i: usize) -> usize {
let j = self.parent[i];
if i == j {
i
} else {
let k = self.find(j);
self.parent[i] = k;
k
}
}
fn union(&mut self, i: usize, j: usize) -> bool {
let i = self.find(i);
let j = self.find(j);
if i != j {
self.parent[i] = j;
self.n -= 1;
true
} else {
false
}
}
}
impl Solution {
fn valid_tree(n: i32, edges: Vec<Vec<i32>>) -> bool {
let n = n as usize;
let mut uf = UnionFind::new(n);
for edge in edges {
let i = edge[0] as usize;
let j = edge[1] as usize;
if !uf.union(i, j) {
return false;
}
}
uf.n == 1
}
}
#[test]
fn test() {
let n = 5;
let edges = vec_vec_i32![[0, 1], [0, 2], [0, 3], [1, 4]];
let res = true;
assert_eq!(Solution::valid_tree(n, edges), res);
let n = 5;
let edges = vec_vec_i32![[0, 1], [1, 2], [2, 3], [1, 3], [1, 4]];
let res = false;
assert_eq!(Solution::valid_tree(n, edges), res);
}