#![allow(unused)] use kyoproio::*; use std::{ collections::*, iter, mem::{replace, swap}, }; fn main() -> io::Result<()> { std::thread::Builder::new() .stack_size(50 * 1024 * 1024) .spawn(solve)? .join() .unwrap(); Ok(()) } fn solve() { let stdin = io::stdin(); let mut kin = KInput::new(stdin.lock()); let stdout = io::stdout(); let mut out = io::BufWriter::new(stdout.lock()); macro_rules! output { ($($args:expr),+) => { write!(&mut out, $($args),+) }; } macro_rules! outputln { ($($args:expr),+) => { output!($($args),+); outputln!() }; () => { output!("\n"); if cfg!(debug_assertions) { out.flush(); } } } let n: usize = kin.input(); let mut g: Vec<_> = iter::repeat_with(Vec::new).take(n).collect(); let mut h: Vec<_> = iter::repeat_with(Vec::new).take(n).collect(); for _ in 0..n - 1 { let (u, v, w): (usize, usize, u64) = kin.input(); g[u].push((v, w)); g[v].push((u, w)); h[u].push(v); h[v].push(u); } let hld = Hld::new(&h, 0); let mut dist = vec![0; n]; dfs(&g, 0, 0, &mut dist); let q: usize = kin.input(); let sum = |u, v| { let a = hld.lca(u, v); dist[u] + dist[v] - 2 * dist[a] }; for (x, y, z) in kin.iter().take(q) { let ans = (sum(x, y) + sum(y, z) + sum(z, x)) / 2; outputln!("{}", ans); } } fn dfs(g: &[Vec<(usize, u64)>], u: usize, p: usize, dist: &mut [u64]) { for &(v, w) in &g[u] { if v != p { dist[v] = dist[u] + w; dfs(g, v, u, dist); } } } #[derive(Debug)] pub struct Hld { head: Vec, par: Vec, tab: Vec, } pub type Graph = [Vec]; impl Hld { pub fn new(g: &Graph, root: usize) -> Self { let mut heavy = vec![!0; g.len()]; Self::dfs_heavy(g, &mut heavy, &mut vec![1; g.len()], root, !0); let mut hld = Hld { head: Vec::with_capacity(g.len()), par: Vec::with_capacity(g.len()), tab: vec![0; g.len()], }; hld.dfs_build(g, &heavy, root, !0, root); hld } fn dfs_heavy(g: &Graph, heavy: &mut [usize], size: &mut [usize], u: usize, p: usize) { let mut max = 0; for &v in g[u].iter().filter(|&&v| v != p) { Self::dfs_heavy(g, heavy, size, v, u); if size[v] > max { max = size[v]; heavy[u] = v; } size[u] += size[v]; } } fn dfs_build(&mut self, g: &Graph, heavy: &[usize], u: usize, p: usize, h: usize) { self.tab[u] = self.head.len(); self.head.push(h); self.par.push(p); if heavy[u] == !0 { return; } self.dfs_build(g, heavy, heavy[u], u, h); for &v in g[u].iter().filter(|&&v| v != p && v != heavy[u]) { self.dfs_build(g, heavy, v, u, v); } } pub fn lca(&self, mut u: usize, mut v: usize) -> usize { loop { if self.tab[u] > self.tab[v] { swap(&mut u, &mut v); } if self.head[self.tab[u]] == self.head[self.tab[v]] { return u; } v = self.par[self.tab[self.head[self.tab[v]]]]; } } } // ----------------------------------------------------------------------------- pub mod kyoproio { #![warn(unused)] pub use std::io::{self, prelude::*}; pub trait Input: Sized { fn str(&mut self) -> &str; fn bytes(&mut self) -> &[u8] { self.str().as_ref() } fn input(&mut self) -> T { self.input_fallible().expect("input error") } fn input_fallible(&mut self) -> Result { T::input(self) } fn iter(&mut self) -> Iter { Iter { input: self, _t: std::marker::PhantomData, } } fn seq>(&mut self, n: usize) -> B { self.iter().take(n).collect() } } pub struct KInput { src: R, buf: String, pos: usize, } impl KInput { pub fn new(src: R) -> Self { Self { src, buf: String::with_capacity(1024), pos: 0, } } } impl Input for KInput { fn str(&mut self) -> &str { loop { if self.pos >= self.buf.len() { self.pos = 0; self.buf.clear(); if self.src.read_line(&mut self.buf).expect("io error") == 0 { return &self.buf; } } let range = self.pos ..self.buf[self.pos..] .find(|c: char| c.is_ascii_whitespace()) .map(|i| i + self.pos) .unwrap_or_else(|| self.buf.len()); self.pos = range.end + 1; if range.end > range.start { return &self.buf[range]; } } } } pub struct Iter<'a, T, I> { input: &'a mut I, _t: std::marker::PhantomData, } impl<'a, T: InputParse, I: Input> Iterator for Iter<'a, T, I> { type Item = T; fn next(&mut self) -> Option { Some(self.input.input()) } } type Result = std::result::Result>; pub trait InputParse: Sized { fn input(input: &mut I) -> Result; } macro_rules! input_from_str_impls { { $($T:ty)* } => { $(impl InputParse for $T { fn input(input: &mut I) -> Result { input.str().parse::<$T>().map_err(|e| e.into()) } })* }; } input_from_str_impls! { String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128 } macro_rules! input_tuple_impls { ($H:ident, $($T:ident),+) => { impl<$H: InputParse, $($T: InputParse),+> InputParse for ($H, $($T),+) { fn input(input: &mut I) -> Result { Ok(($H::input(input)?, $($T::input(input)?),+)) } } input_tuple_impls!($($T),+); }; ($H:ident) => {}; } input_tuple_impls!(A, B, C, D, E, F, G); /* impl InputParse for [T; N] { fn input(input: &mut I) -> Result { let mut a = std::mem::MaybeUninit::<[T; N]>::uninit(); for i in 0..N { match T::input(input) { Ok(v) => unsafe { std::ptr::write(&mut (*a.as_mut_ptr())[i], v) }, Err(e) => unsafe { std::ptr::drop_in_place(&mut (*a.as_mut_ptr())[..i]); return Err(e); }, } } Ok(unsafe { a.assume_init() }) } } */ }