結果

問題 No.898 tri-βutree
コンテスト
ユーザー cotton_fn_
提出日時 2020-03-28 16:29:37
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 261 ms / 4,000 ms
コード長 7,319 bytes
コンパイル時間 15,417 ms
コンパイル使用メモリ 378,928 KB
実行使用メモリ 34,868 KB
最終ジャッジ日時 2024-11-08 23:31:57
合計ジャッジ時間 21,650 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 21
権限があれば一括ダウンロードができます

ソースコード

diff # 

#![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<usize>,
    par: Vec<usize>,
    tab: Vec<usize>,
}
pub type Graph = [Vec<usize>];
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<T: InputParse>(&mut self) -> T {
            self.input_fallible().expect("input error")
        }
        fn input_fallible<T: InputParse>(&mut self) -> Result<T> {
            T::input(self)
        }
        fn iter<T: InputParse>(&mut self) -> Iter<T, Self> {
            Iter {
                input: self,
                _t: std::marker::PhantomData,
            }
        }
        fn seq<T: InputParse, B: std::iter::FromIterator<T>>(&mut self, n: usize) -> B {
            self.iter().take(n).collect()
        }
    }
    pub struct KInput<R> {
        src: R,
        buf: String,
        pos: usize,
    }
    impl<R: BufRead> KInput<R> {
        pub fn new(src: R) -> Self {
            Self {
                src,
                buf: String::with_capacity(1024),
                pos: 0,
            }
        }
    }
    impl<R: BufRead> Input for KInput<R> {
        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<T>,
    }
    impl<'a, T: InputParse, I: Input> Iterator for Iter<'a, T, I> {
        type Item = T;
        fn next(&mut self) -> Option<Self::Item> {
            Some(self.input.input())
        }
    }
    type Result<T> = std::result::Result<T, Box<dyn std::error::Error + 'static>>;
    pub trait InputParse: Sized {
        fn input<I: Input>(input: &mut I) -> Result<Self>;
    }
    macro_rules! input_from_str_impls {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                fn input<I: Input>(input: &mut I) -> Result<Self> {
                    input.str().parse::<$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<I: Input>(input: &mut I) -> Result<Self> {
                    Ok(($H::input(input)?, $($T::input(input)?),+))
                }
            }
            input_tuple_impls!($($T),+);
        };
        ($H:ident) => {};
    }
    input_tuple_impls!(A, B, C, D, E, F, G);
    /*
    impl<T: InputParse, const N: usize> InputParse for [T; N] {
        fn input<I: Input>(input: &mut I) -> Result<Self> {
            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() })
        }
    }
    */
}
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