#[allow(unused_imports)] use std::cmp::*; #[allow(unused_imports)] use std::collections::*; use std::io::{Write, BufWriter}; // https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { ($($r:tt)*) => { let stdin = std::io::stdin(); let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next = move || -> String{ bytes .by_ref() .map(|r|r.unwrap() as char) .skip_while(|c|c.is_whitespace()) .take_while(|c|!c.is_whitespace()) .collect() }; input_inner!{next, $($r)*} }; } macro_rules! input_inner { ($next:expr) => {}; ($next:expr, ) => {}; ($next:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($next, $t); input_inner!{$next $($r)*} }; } macro_rules! read_value { ($next:expr, ( $($t:tt),* )) => { ( $(read_value!($next, $t)),* ) }; ($next:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($next, $t)).collect::>() }; ($next:expr, chars) => { read_value!($next, String).chars().collect::>() }; ($next:expr, usize1) => { read_value!($next, usize) - 1 }; ($next:expr, [ $t:tt ]) => {{ let len = read_value!($next, usize); (0..len).map(|_| read_value!($next, $t)).collect::>() }}; ($next:expr, $t:ty) => { $next().parse::<$t>().expect("Parse error") }; } #[allow(unused)] macro_rules! debug { ($($format:tt)*) => (write!(std::io::stderr(), $($format)*).unwrap()); } #[allow(unused)] macro_rules! debugln { ($($format:tt)*) => (writeln!(std::io::stderr(), $($format)*).unwrap()); } /// Lowest Common Ancestor. Call lca(x, y) to get the lca of them. /// Many-rooted version. /// Verified by: https://yukicoder.me/submissions/413634 pub struct LowestCommonAncestor { n: usize, bn: usize, parent: Vec, // r is root <=> parent[r] = r dep: Vec, lca_tbl: Vec> } impl LowestCommonAncestor { fn dfs(&mut self, edges: &[Vec], v: usize, par: usize, d: usize) { self.parent[v] = par; self.dep[v] = d; for &u in edges[v].iter() { if u != par { self.dfs(edges, u, v, d + 1); } } } fn lca_init(&mut self) { let n = self.n; for v in 0 .. n { self.lca_tbl[v] = vec![0; self.bn + 1]; self.lca_tbl[v][0] = self.parent[v]; } for i in 1 .. self.bn + 1 { for v in 0 .. n { self.lca_tbl[v][i] = self.lca_tbl[self.lca_tbl[v][i - 1]][i - 1]; } } } pub fn lca(&self, mut x: usize, mut y: usize) -> usize { let dx = self.dep[x]; let mut dy = self.dep[y]; if dx > dy { return self.lca(y, x); } for l in (0 .. self.bn + 1).rev() { if dy - dx >= 1 << l { y = self.lca_tbl[y][l]; dy -= 1 << l; } } assert_eq!(dx, dy); if x == y { return x; } for l in (0 .. self.bn + 1).rev() { if self.lca_tbl[x][l] != self.lca_tbl[y][l] { x = self.lca_tbl[x][l]; y = self.lca_tbl[y][l]; } } self.lca_tbl[x][0] } #[allow(unused)] pub fn depth(&self, a: usize) -> usize { self.dep[a] } #[allow(unused)] pub fn parent(&self, a: usize) -> usize { self.parent[a] } pub fn new(edges: &[Vec], roots: &[usize]) -> Self { let n = edges.len(); let bn = (n.next_power_of_two() - 1).count_ones() as usize; let mut ret = LowestCommonAncestor { n: n, bn: bn, parent: vec![0; n], dep: vec![0; n], lca_tbl: vec![Vec::new(); n] }; for &r in roots { ret.dfs(edges, r, r, 0); } ret.lca_init(); ret } } fn dfs(g: &[Vec<(usize, i64)>], v: usize, par: usize, dep: &mut [i64], d: i64) { dep[v] = d; for &(w, c) in &g[v] { if w == par { continue; } dfs(g, w, v, dep, d + c); } } fn solve() { let out = std::io::stdout(); let mut out = BufWriter::new(out.lock()); macro_rules! puts { ($($format:tt)*) => (write!(out,$($format)*).unwrap()); } input! { n: usize, uvw: [(usize, usize, i64); n - 1], xyz: [(usize, usize, usize)], } let mut g = vec![vec![]; n]; let mut gw = vec![vec![]; n]; for &(u, v, w) in &uvw { g[u].push(v); g[v].push(u); gw[u].push((v, w)); gw[v].push((u, w)); } let mut dep = vec![0; n]; dfs(&gw, 0, n, &mut dep, 0); let lca = LowestCommonAncestor::new(&g, &[0]); for &(x, y, z) in &xyz { let l0 = lca.lca(x, y); let l1 = lca.lca(x, z); let l2 = lca.lca(y, z); let l = lca.lca(l0, z); let dsum = dep[x] + dep[y] + dep[z]; let ans = if l0 != l { dsum - dep[l0] - 2 * dep[l] } else if l1 != l { dsum - dep[l1] - 2 * dep[l] } else if l2 != l { dsum - dep[l2] - 2 * dep[l] } else { dsum - 3 * dep[l] }; puts!("{}\n", ans); } debugln!("dep = {:?}", dep); } fn main() { // In order to avoid potential stack overflow, spawn a new thread. let stack_size = 104_857_600; // 100 MB let thd = std::thread::Builder::new().stack_size(stack_size); thd.spawn(|| solve()).unwrap().join().unwrap(); }