struct UnionFind { n: usize, parents: Vec, depths: Vec, chains: Vec, } impl UnionFind { fn new(n: usize) -> Self { UnionFind { n: n, parents: (0..n).collect(), depths: vec![0; n], chains: vec![1; n], } } fn equiv(&mut self, a: usize, b: usize) -> bool { self.find(a) == self.find(b) } fn unite(&mut self, a: usize, b: usize) { if self.equiv(a, b) { return; } let x = self.parents[a]; let y = self.parents[b]; if self.depths[x] > self.depths[y] { self.parents[x] = self.parents[y]; self.chains[y] += self.chains[x]; } else { self.parents[y] = self.parents[x]; self.chains[x] += self.chains[y]; if self.depths[x] == self.depths[y] { self.depths[x] += 1; } } } fn find(&mut self, a: usize) -> usize { if self.parents[a] == a { return a; } let p = self.find(self.parents[a]); self.parents[a] = p; p } fn chain_cnt(&mut self, i: usize) -> usize { let idx = self.find(i); self.chains[idx] } } fn main() { let mut n = String::new(); std::io::stdin().read_line(&mut n).ok(); let n: usize = n.trim().parse().unwrap(); let mut uf = UnionFind::new(n); let mut cnt = 0usize; for _ in 0.. { let mut temp = String::new(); std::io::stdin().read_line(&mut temp).ok(); let temp: Vec<&str> = temp.trim().split_whitespace().collect(); let a = temp[0].parse::().unwrap()-1; let b = temp[1].parse::().unwrap()-1; let c = temp[2]; if uf.find(a) == uf.find(b) { continue; } uf.unite(a, b); cnt += 1; if cnt == n-1 { println!("{}", c); return; } } }