結果

問題 No.2337 Equidistant
ユーザー akakimidoriakakimidori
提出日時 2023-06-02 22:01:17
言語 Rust
(1.77.0 + proconio)
結果
AC  
実行時間 317 ms / 4,000 ms
コード長 9,063 bytes
コンパイル時間 17,507 ms
コンパイル使用メモリ 379,456 KB
実行使用メモリ 38,492 KB
最終ジャッジ日時 2024-06-08 23:06:31
合計ジャッジ時間 25,096 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
5,248 KB
testcase_01 AC 1 ms
5,376 KB
testcase_02 AC 1 ms
5,376 KB
testcase_03 AC 2 ms
5,376 KB
testcase_04 AC 1 ms
5,376 KB
testcase_05 AC 1 ms
5,376 KB
testcase_06 AC 2 ms
5,376 KB
testcase_07 AC 2 ms
5,376 KB
testcase_08 AC 2 ms
5,376 KB
testcase_09 AC 2 ms
5,376 KB
testcase_10 AC 2 ms
5,376 KB
testcase_11 AC 284 ms
34,676 KB
testcase_12 AC 278 ms
34,672 KB
testcase_13 AC 286 ms
34,804 KB
testcase_14 AC 283 ms
34,804 KB
testcase_15 AC 275 ms
34,672 KB
testcase_16 AC 272 ms
34,676 KB
testcase_17 AC 262 ms
34,636 KB
testcase_18 AC 261 ms
34,796 KB
testcase_19 AC 283 ms
34,668 KB
testcase_20 AC 267 ms
34,620 KB
testcase_21 AC 160 ms
37,844 KB
testcase_22 AC 164 ms
38,492 KB
testcase_23 AC 195 ms
35,372 KB
testcase_24 AC 288 ms
36,956 KB
testcase_25 AC 202 ms
35,720 KB
testcase_26 AC 317 ms
36,828 KB
testcase_27 AC 238 ms
35,796 KB
testcase_28 AC 224 ms
35,672 KB
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 # 

use std::io::Write;

fn run() {
    input! {
        n: usize,
        q: usize,
        e: [(usize1, usize1); n - 1],
        ask: [(usize1, usize1); q],
    }
    let mut hld = HLD::new(n);
    for (a, b) in e {
        hld.add_edge(a, b);
    }
    hld.build(0);
    let out = std::io::stdout();
    let mut out = std::io::BufWriter::new(out.lock());
    let mut up = vec![];
    let mut down = vec![];
    let mut solve = |s: usize, t: usize| -> i32 {
        assert!(s != t);
        hld.path(s, t, &mut up, &mut down);
        let len = up.iter().chain(down.iter()).fold(0, |s, p| s + p.1 - p.0);
        if len % 2 == 0 {
            return 0;
        }
        let mid = hld.jump(s, t, len / 2, &mut up, &mut down).unwrap();
        let mut ans = n as i32;
        for &x in [s, t].iter() {
            let v = hld.next(mid, x);
            if hld.parent(v).map_or(false, |p| p == mid) {
                let p = hld.sub_tree(v);
                ans -= (p.1 - p.0) as i32;
            } else {
                let p = hld.sub_tree(mid);
                ans -= (n - (p.1 - p.0)) as i32;
            }
        }
        ans
    };
    for (s, t) in ask {
        let ans = solve(s, t);
        writeln!(out, "{}", ans).ok();
    }
}

fn main() {
    run();
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------
// ---------- begin Heavy-Light decomposition ----------
pub struct HLD {
    size: usize,
    edge: Vec<(usize, usize)>,
    child: Vec<Vec<usize>>,
    path_root: Vec<usize>,
    parent: Vec<usize>,
    left: Vec<usize>,
    right: Vec<usize>,
    inverse: Vec<usize>,
}

impl HLD {
    pub fn new(size: usize) -> Self {
        assert!(size <= 10usize.pow(8));
        HLD {
            size: size,
            edge: Vec::with_capacity(size - 1),
            child: Vec::new(),
            path_root: Vec::new(),
            parent: Vec::new(),
            left: Vec::new(),
            right: Vec::new(),
            inverse: Vec::new(),
        }
    }
    pub fn add_edge(&mut self, a: usize, b: usize) {
        assert!(a != b && a < self.size && b < self.size);
        self.edge.push((a, b));
    }
    pub fn build(&mut self, root: usize) {
        assert!(self.edge.len() + 1 == self.size);
        let size = self.size;
        let mut cnt = vec![0; size];
        for &(a, b) in self.edge.iter() {
            cnt[a] += 1;
            cnt[b] += 1;
        }
        let mut child = cnt
            .into_iter()
            .map(|c| Vec::with_capacity(c))
            .collect::<Vec<_>>();
        for &(a, b) in self.edge.iter() {
            child[a].push(b);
            child[b].push(a);
        }
        let mut parent = vec![size; size];
        let mut q = Vec::with_capacity(size);
        q.push(root);
        parent[root] = root;
        for i in 0..size {
            let v = q[i];
            for u in child[v].clone() {
                assert!(parent[u] == size);
                parent[u] = v;
                child[u].retain(|e| *e != v);
                q.push(u);
            }
        }
        let mut sum = vec![1; size];
        for &v in q.iter().rev() {
            let child = &mut child[v];
            if !child.is_empty() {
                let (pos, _) = child.iter().enumerate().max_by_key(|p| sum[*p.1]).unwrap();
                child.swap(0, pos);
                sum[v] = 1 + child.iter().fold(0, |s, a| s + sum[*a]);
            }
        }
        let mut path_root = (0..size).collect::<Vec<_>>();
        let mut left = vec![0; size];
        let mut right = vec![0; size];
        let mut dfs = vec![(root, false)];
        let mut id = 0;
        while let Some((v, end)) = dfs.pop() {
            if end {
                right[v] = id;
                continue;
            }
            left[v] = id;
            id += 1;
            dfs.push((v, true));
            let child = &child[v];
            if !child.is_empty() {
                for &u in child[1..].iter() {
                    path_root[u] = u;
                    dfs.push((u, false));
                }
                let u = child[0];
                path_root[u] = path_root[v];
                dfs.push((u, false));
            }
        }
        let mut inverse = vec![size; size];
        for (i, l) in left.iter().enumerate() {
            inverse[*l] = i;
        }
        self.child = child;
        self.parent = parent;
        self.left = left;
        self.right = right;
        self.path_root = path_root;
        self.inverse = inverse;
    }
    pub fn lca(&self, mut a: usize, mut b: usize) -> usize {
        assert!(a < self.size && b < self.size);
        let path = &self.path_root;
        let parent = &self.parent;
        let index = &self.left;
        while path[a] != path[b] {
            if index[a] > index[b] {
                std::mem::swap(&mut a, &mut b);
            }
            b = parent[path[b]];
        }
        std::cmp::min((index[a], a), (index[b], b)).1
    }
    pub fn path(
        &self,
        src: usize,
        dst: usize,
        up: &mut Vec<(usize, usize)>,
        down: &mut Vec<(usize, usize)>,
    ) {
        assert!(src < self.size && dst < self.size);
        up.clear();
        down.clear();
        let path = &self.path_root;
        let parent = &self.parent;
        let index = &self.left;
        let mut x = src;
        let mut y = dst;
        while path[x] != path[y] {
            if index[x] > index[y] {
                let p = path[x];
                assert!(p == path[p]);
                up.push((index[p], index[x] + 1));
                x = parent[p];
            } else {
                let p = path[y];
                assert!(p == path[p]);
                down.push((index[p], index[y] + 1));
                y = parent[p];
            }
        }
        if index[x] <= index[y] {
            down.push((index[x], index[y] + 1));
        } else {
            up.push((index[y], index[x] + 1));
        }
        down.reverse();
    }
    pub fn sub_tree(&self, v: usize) -> (usize, usize) {
        assert!(v < self.size);
        (self.left[v], self.right[v])
    }
    pub fn parent(&self, v: usize) -> Option<usize> {
        assert!(v < self.size);
        let p = self.parent[v];
        if p == v {
            None
        } else {
            Some(p)
        }
    }
    // s -> t へのパスの2番目の頂点を返す
    pub fn next(&self, s: usize, t: usize) -> usize {
        assert!(s < self.size && t < self.size && s != t);
        let (a, b) = self.sub_tree(s);
        let (c, d) = self.sub_tree(t);
        if !(a <= c && d <= b) {
            return self.parent[s];
        }
        let mut pos = t;
        let mut pre = t;
        while self.path_root[s] != self.path_root[pos] {
            pre = self.path_root[pos];
            pos = self.parent[pre];
        }
        if s == pos {
            pre
        } else {
            self.child[s][0]
        }
    }
    pub fn vertex(&self, x: usize) -> usize {
        assert!(x < self.size);
        self.inverse[x]
    }
    pub fn jump(&self, s: usize, t: usize, mut k: usize, up: &mut Vec<(usize, usize)>, down: &mut Vec<(usize, usize)>) -> Option<usize> {
        assert!(s.max(t) < self.size);
        self.path(s, t, up, down);
        for (l, r) in up.drain(..) {
            if k < r - l {
                return Some(self.vertex(r - 1 - k));
            }
            k -= r - l;
        }
        for (l, r) in down.drain(..) {
            if k < r - l {
                return Some(self.vertex(l + k));
            }
            k -= r - l;
        }
        None
    }
}
// ---------- end Heavy-Light decomposition ----------
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