結果

問題 No.898 tri-βutree
コンテスト
ユーザー koba-e964
提出日時 2020-01-03 23:01:19
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 666 ms / 4,000 ms
コード長 5,686 bytes
コンパイル時間 15,343 ms
コンパイル使用メモリ 379,040 KB
実行使用メモリ 53,504 KB
最終ジャッジ日時 2024-11-08 23:18:36
合計ジャッジ時間 26,641 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge3
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_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::<Vec<_>>()
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, [ $t:tt ]) => {{
        let len = read_value!($next, usize);
        (0..len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    }};

    ($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<usize>, // r is root <=> parent[r] = r
    dep: Vec<usize>,
    lca_tbl: Vec<Vec<usize>>
}

impl LowestCommonAncestor {
    fn dfs(&mut self, edges: &[Vec<usize>], 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<usize>], 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();
}
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