#1153393 (Rust) No.1787 Do Use Dynamic Tree

• 問題: No.1787 Do Use Dynamic Tree
• ユーザー: akakimidori
• 提出日時: 2026-03-22 09:28:06
• 言語: Rust (1.93.0 + proconio + num + itertools)
• 結果: AC
• 実行時間: 1,132 ms / 10,000 ms
• コード長: 20,150 bytes
• コンパイル時間: 14,473 ms
• コンパイル使用メモリ: 222,660 KB
• 実行使用メモリ: 80,696 KB
• 最終ジャッジ日時: 2026-03-22 09:28:34
• 合計ジャッジ時間: 13,060 ms
• ジャッジサーバーID （参考情報）: judge3_0 / judge2_0

ファイルパターン	結果
sample	AC * 2
other	AC * 38

コンパイルメッセージ

warning: unused variable: `e`
  --> src/main.rs:38:40
   |
38 |     fn add_edge(&self, p: &Self::Path, e: &Self::Edge) -> Self::Point {
   |                                        ^ help: if this is intentional, prefix it with an underscore: `_e`
   |
   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default

warning: unused variable: `e`
  --> src/main.rs:47:56
   |
47 |     fn compress(&self, p: &Self::Path, c: &Self::Path, e: &Self::Edge) -> Self::Path {
   |                                                        ^ help: if this is intentional, prefix it with an underscore: `_e`

ソースコード

fn main() {
    let (e, ask) = read();
    let n = e.len() + 1;
    let mut val = (1..=(n as i32)).collect::<Vec<_>>();
    let p = val.iter().enumerate().map(|p| (*p.1, p.0 as i32)).collect::<Vec<_>>();
    let mut solver = RerootingDP::new(
        R,
        p,
        e.into_iter().map(|e| (e.0, e.1, ())).collect::<Vec<_>>(),
    );
    let mut ans = vec![0; ask.len()];
    let mut pre = 0;
    for (ans, (u, v)) in ans.iter_mut().zip(ask) {
        let u = (u + pre) % n;
        let v = (v + pre) % n;
        val.swap(u, v);
        solver.set_vertex(u, (val[u], u as i32));
        solver.set_vertex(v, (val[v], v as i32));
        let p = solver.find(u);
        *ans = p.2 + 1;
        pre = *ans as usize;
    }
    use util::*;
    println!("{}", ans.iter().join("\n"));
}

struct R;
impl TreeDP for R {
    type Vertex = (i32, i32);
    type Edge = ();
    // パスの始点、繋がってるなら次の頂点、端
    type Path = (i32, i32, i32);
    // パスの始点、終端
    type Point = (i32, i32);
    fn vertex(&self, v: &Self::Vertex) -> Self::Path {
        (v.0, 0, v.1)
    }
    fn add_edge(&self, p: &Self::Path, e: &Self::Edge) -> Self::Point {
        (p.0, p.2)
    }
    fn rake(&self, a: &Self::Point, b: &Self::Point) -> Self::Point {
        std::cmp::max(*a, *b)
    }
    fn add_vertex(&self, p: &Self::Point, v: &Self::Vertex) -> Self::Path {
        (v.0, p.0, p.1)
    }
    fn compress(&self, p: &Self::Path, c: &Self::Path, e: &Self::Edge) -> Self::Path {
        if p.1 >= 0 && c.0 > p.1 {
            (p.0, c.1, c.2)
        } else {
            (p.0, -1, p.2)
        }
    }
}

fn read() -> (Vec<(usize, usize)>, Vec<(usize, usize)>) {
    let mut s = String::new();
    use std::io::*;
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut it = s.trim().split_whitespace().flat_map(|s| s.parse::<usize>());
    let mut next = || it.next().unwrap();
    let n = next();
    let e = (1..n)
        .map(|_| {
            let a = next() - 1;
            let b = next() - 1;
            (a, b)
        })
        .collect();
    let q = next();
    let ask = (0..q)
        .map(|_| {
            let a = next() - 1;
            let b = next() - 1;
            (a, b)
        })
        .collect();
    (e, ask)
}

pub trait TreeDP {
    type Vertex: Clone;
    type Edge: Clone;
    type Path: Clone;
    type Point: Clone;
    fn vertex(&self, v: &Self::Vertex) -> Self::Path;
    fn add_edge(&self, p: &Self::Path, e: &Self::Edge) -> Self::Point;
    fn rake(&self, a: &Self::Point, b: &Self::Point) -> Self::Point;
    fn add_vertex(&self, p: &Self::Point, v: &Self::Vertex) -> Self::Path;
    fn compress(&self, p: &Self::Path, c: &Self::Path, e: &Self::Edge) -> Self::Path;
}

pub struct RerootingDP<R, V, E, A, B> {
    op: R,
    v: Vec<V>,
    e: Vec<E>,
    sum: Vec<Union<(A, A), B>>,
    stt: StaticTopTree,
}

impl<R> RerootingDP<R, R::Vertex, R::Edge, R::Path, R::Point>
where
    R: TreeDP,
{
    const ROOT: usize = 0;
    pub fn new(op: R, v: Vec<R::Vertex>, edge: Vec<(usize, usize, R::Edge)>) -> Self {
        assert!(v.len() == edge.len() + 1);
        let mut e = vec![];
        let mut memo = vec![];
        for (a, b, w) in edge {
            e.push(w);
            memo.push((a, b));
        }
        let stt = StaticTopTree::new(memo, Self::ROOT);
        let sum = vec![Union::V((op.vertex(&v[0]), op.vertex(&v[0]))); stt.label.len()];
        let mut res = Self { op, v, e, sum, stt };
        for i in 0..res.stt.label.len() {
            res.pull(i);
        }
        res
    }
    pub fn set_vertex(&mut self, v: usize, w: R::Vertex) {
        self.v[v] = w;
        self.update(self.stt.vertex[v]);
    }
    pub fn set_edge(&mut self, e: usize, w: R::Edge) {
        self.e[e] = w;
        self.update(self.stt.edge[e]);
    }
    pub fn find(&self, root: usize) -> R::Path {
        if root == Self::ROOT {
            return self.sum.last().unwrap().get_v().0.clone();
        }
        // なんか非常に汚い、もっと綺麗に書けないか
        let mut pos = self.stt.vertex[root];
        let mut memo = vec![];
        while let Some(p) = self.stt.node[pos].p.get() {
            let l = self.stt.node[p].l.get().unwrap() == pos;
            pos = p;
            memo.push((p, l));
        }
        let mut up: Option<(R::Path, R::Edge)> = None;
        let mut down: Option<(R::Path, R::Edge)> = None;
        let mut point: Option<R::Point> = None;
        let mut vertex: Option<R::Vertex> = None;
        for &(pos, left) in memo.iter().rev() {
            if self.stt.label[pos] == STTLabel::Compress {
                let e = &self.e[self.stt.node[pos].e.get().unwrap()];
                if left {
                    let r = self.stt.node[pos].r.get().unwrap();
                    let r = &self.sum[r].get_v().0;
                    down = Some(down.map_or((r.clone(), e.clone()), |(a, b)| {
                        (self.op.compress(r, &a, &b), e.clone())
                    }));
                } else {
                    let l = self.stt.node[pos].l.get().unwrap();
                    let l = &self.sum[l].get_v().1;
                    up = Some(up.map_or((l.clone(), e.clone()), |(a, b)| {
                        (self.op.compress(l, &a, &b), e.clone())
                    }));
                }
            } else if self.stt.label[pos] == STTLabel::AddVertex {
                vertex = Some(self.v[self.stt.node[pos].e.get().unwrap()].clone());
                let u = up.take().map(|p| self.op.add_edge(&p.0, &p.1));
                let d = down.take().map(|p| self.op.add_edge(&p.0, &p.1));
                point = match (u, d) {
                    (Some(a), Some(b)) => Some(self.op.rake(&a, &b)),
                    (a, b) => a.or(b),
                };
            } else if self.stt.label[pos] == STTLabel::Rake {
                let other = if left {
                    self.stt.node[pos].r
                } else {
                    self.stt.node[pos].l
                }
                .get()
                .unwrap();
                let p = self.sum[other].get_e();
                point = Some(point.map_or(p.clone(), |q| self.op.rake(p, &q)));
            } else if self.stt.label[pos] == STTLabel::AddEdge {
                let e = &self.e[self.stt.node[pos].e.get().unwrap()];
                if point.is_some() {
                    let p = point.take().unwrap();
                    let v = vertex.take().unwrap();
                    up = Some((self.op.add_vertex(&p, &v), e.clone()));
                } else {
                    unreachable!()
                }
            } else {
                unreachable!()
            }
        }
        let pos = self.stt.vertex[root];
        if self.stt.label[pos] == STTLabel::AddVertex {
            let u = up.map(|p| self.op.add_edge(&p.0, &p.1));
            let d = down.map(|p| self.op.add_edge(&p.0, &p.1));
            let p = match (u, d) {
                (Some(a), Some(b)) => Some(self.op.rake(&a, &b)),
                (a, b) => a.or(b),
            }
            .unwrap();
            let c = self.sum[self.stt.node[pos].l.get().unwrap()].get_e();
            let q = self.op.rake(&p, c);
            self.op.add_vertex(&q, &self.v[root])
        } else {
            let u = up.map(|p| self.op.add_edge(&p.0, &p.1));
            let d = down.map(|p| self.op.add_edge(&p.0, &p.1));
            let p = match (u, d) {
                (Some(a), Some(b)) => Some(self.op.rake(&a, &b)),
                (a, b) => a.or(b),
            }
            .unwrap();
            self.op.add_vertex(&p, &self.v[root])
        }
    }
    fn update(&mut self, mut v: usize) {
        self.pull(v);
        while let Some(p) = self.stt.node[v].p.get() {
            v = p;
            self.pull(p);
        }
    }
    fn pull(&mut self, v: usize) {
        match self.stt.label[v] {
            STTLabel::Vertex => {
                let u = self.stt.node[v].e.get().unwrap();
                let p = self.op.vertex(&self.v[u]);
                self.sum[v].set_v((p.clone(), p));
            }
            STTLabel::AddEdge => {
                let l = self.stt.node[v].l.get().unwrap();
                let e = self.stt.node[v].e.get().unwrap();
                let path = &self.sum[l].get_v().0;
                let point = self.op.add_edge(path, &self.e[e]);
                self.sum[v].set_e(point);
            }
            STTLabel::Rake => {
                let l = self.stt.node[v].l.get().unwrap();
                let r = self.stt.node[v].r.get().unwrap();
                let point = self.op.rake(self.sum[l].get_e(), self.sum[r].get_e());
                self.sum[v].set_e(point);
            }
            STTLabel::AddVertex => {
                let l = self.stt.node[v].l.get().unwrap();
                let u = self.stt.node[v].e.get().unwrap();
                let path = self.op.add_vertex(self.sum[l].get_e(), &self.v[u]);
                self.sum[v].set_v((path.clone(), path));
            }
            STTLabel::Compress => {
                let l = self.sum[self.stt.node[v].l.get().unwrap()].get_v();
                let r = self.sum[self.stt.node[v].r.get().unwrap()].get_v();
                let e = self.stt.node[v].e.get().unwrap();
                let lr = self.op.compress(&l.0, &r.0, &self.e[e]);
                let rl = self.op.compress(&r.1, &l.1, &self.e[e]);
                self.sum[v].set_v((lr, rl));
            }
        }
    }
}

pub struct FixRootTreeDP<R, V, E, A, B> {
    op: R,
    v: Vec<V>,
    e: Vec<E>,
    sum: Vec<Union<A, B>>,
    stt: StaticTopTree,
}

impl<R> FixRootTreeDP<R, R::Vertex, R::Edge, R::Path, R::Point>
where
    R: TreeDP,
{
    pub fn new(op: R, v: Vec<R::Vertex>, edge: Vec<(usize, usize, R::Edge)>) -> Self {
        assert!(v.len() == edge.len() + 1);
        let mut e = vec![];
        let mut memo = vec![];
        for (a, b, w) in edge {
            e.push(w);
            memo.push((a, b));
        }
        let stt = StaticTopTree::new(memo, 0);
        let sum = vec![Union::V(op.vertex(&v[0])); stt.label.len()];
        let mut res = Self { op, v, e, sum, stt };
        for i in 0..res.stt.label.len() {
            res.pull(i);
        }
        res
    }
    pub fn set_vertex(&mut self, v: usize, w: R::Vertex) {
        self.v[v] = w;
        self.update(self.stt.vertex[v]);
    }
    pub fn set_edge(&mut self, e: usize, w: R::Edge) {
        self.e[e] = w;
        self.update(self.stt.edge[e]);
    }
    pub fn find(&self) -> R::Path {
        self.sum.last().unwrap().get_v().clone()
    }
    fn update(&mut self, mut v: usize) {
        self.pull(v);
        while let Some(p) = self.stt.node[v].p.get() {
            v = p;
            self.pull(p);
        }
    }
    fn pull(&mut self, v: usize) {
        match self.stt.label[v] {
            STTLabel::Vertex => {
                let u = self.stt.node[v].e.get().unwrap();
                self.sum[v].set_v(self.op.vertex(&self.v[u]));
            }
            STTLabel::AddEdge => {
                let l = self.stt.node[v].l.get().unwrap();
                let e = self.stt.node[v].e.get().unwrap();
                let path = self.sum[l].get_v();
                let point = self.op.add_edge(path, &self.e[e]);
                self.sum[v].set_e(point);
            }
            STTLabel::Rake => {
                let l = self.stt.node[v].l.get().unwrap();
                let r = self.stt.node[v].r.get().unwrap();
                let point = self.op.rake(self.sum[l].get_e(), self.sum[r].get_e());
                self.sum[v].set_e(point);
            }
            STTLabel::AddVertex => {
                let l = self.stt.node[v].l.get().unwrap();
                let u = self.stt.node[v].e.get().unwrap();
                let path = self.op.add_vertex(self.sum[l].get_e(), &self.v[u]);
                self.sum[v].set_v(path);
            }
            STTLabel::Compress => {
                let l = self.sum[self.stt.node[v].l.get().unwrap()].get_v();
                let r = self.sum[self.stt.node[v].r.get().unwrap()].get_v();
                let e = self.stt.node[v].e.get().unwrap();
                let path = self.op.compress(l, r, &self.e[e]);
                self.sum[v].set_v(path);
            }
        }
    }
}

#[derive(Clone, Debug)]
enum Union<V, E> {
    V(V),
    E(E),
}

impl<V, E> Union<V, E> {
    fn set_v(&mut self, v: V) {
        *self = Self::V(v);
    }
    fn set_e(&mut self, e: E) {
        *self = Self::E(e);
    }
    fn get_v(&self) -> &V {
        let Union::V(ref v) = self else {
            unreachable!()
        };
        v
    }
    fn get_e(&self) -> &E {
        let Union::E(ref v) = self else {
            unreachable!()
        };
        v
    }
}

#[derive(Debug, Clone, Copy, Eq, PartialEq)]
enum STTLabel {
    Vertex,
    AddEdge,
    Rake,
    AddVertex,
    Compress,
}

#[derive(Clone, Debug)]
struct STTNode {
    p: Pointer,
    l: Pointer,
    r: Pointer,
    e: Pointer,
}

impl STTNode {
    fn new(l: Pointer, r: Pointer, e: Pointer) -> Self {
        Self {
            p: Pointer::null(),
            l,
            r,
            e,
        }
    }
}

pub struct StaticTopTree {
    label: Vec<STTLabel>,
    node: Vec<STTNode>,
    height: Vec<usize>,
    vertex: Vec<usize>,
    edge: Vec<usize>,
    size: usize,
}

impl StaticTopTree {
    pub fn new(edge: Vec<(usize, usize)>, root: usize) -> Self {
        let size = edge.len() + 1;
        let mut graph = vec![vec![]; size];
        for (i, &(a, b)) in edge.iter().enumerate() {
            graph[a].push((b, i));
            graph[b].push((a, i));
        }
        let mut topo = vec![root];
        let mut parent = vec![(size, size); size];
        let mut inv_edge = vec![size; size];
        for i in 0..size {
            let v = topo[i];
            for (u, k) in graph[v].clone() {
                graph[u].retain(|p| p.0 != v);
                parent[u] = (v, k);
                inv_edge[k] = u;
                topo.push(u);
            }
        }
        let mut s = vec![1i32; size];
        for &v in topo.iter().rev() {
            let c = &mut graph[v];
            for i in 1..c.len() {
                if s[c[i].0] > s[c[0].0] {
                    c.swap(0, i);
                }
            }
            s[v] += c.iter().map(|e| s[e.0]).sum::<i32>();
        }
        let mut stt = Self {
            label: vec![],
            node: vec![],
            height: vec![],
            vertex: vec![!0; size],
            edge: vec![!0; size - 1],
            size,
        };
        let mut id = vec![!0; size];
        let mut array = vec![None; 128];
        for &v in topo.iter().rev() {
            if graph[v].len() <= 1 {
                id[v] = stt.append_inner(!0, !0, v, STTLabel::Vertex);
            } else {
                let mut bit = 0u128;
                for &(u, e) in graph[v][1..].iter() {
                    let mut k = stt.append_inner(id[u], !0, e, STTLabel::AddEdge);
                    let mut h = stt.height[k];
                    while let Some(x) = array[h].take() {
                        bit ^= 1 << h;
                        k = stt.append_inner(k, x, !0, STTLabel::Rake);
                        h = stt.height[k];
                    }
                    array[h] = Some(k);
                    bit |= 1 << h;
                }
                let x = bit.trailing_zeros() as usize;
                let mut k = array[x].take().unwrap();
                bit ^= 1 << x;
                while bit > 0 {
                    let x = bit.trailing_zeros() as usize;
                    let u = array[x].take().unwrap();
                    k = stt.append_inner(k, u, !0, STTLabel::Rake);
                    bit ^= 1 << x;
                }
                id[v] = stt.append_inner(k, !0, v, STTLabel::AddVertex);
            }
            if v == root || graph[parent[v].0][0].0 != v {
                let mut stack = vec![(id[v], size)];
                let mut pos = v;
                while let Some(&(u, k)) = graph[pos].get(0) {
                    stack.push((id[u], k));
                    while stack.len() > 1 {
                        let len = stack.len();
                        let (b, a) = (stack[len - 2], stack[len - 1]);
                        if len >= 3 && stt.height[stack[len - 3].0] <= stt.height[a.0] {
                            let c = stack[len - 3];
                            stack.truncate(len - 3);
                            let v = stt.append_inner(c.0, b.0, b.1, STTLabel::Compress);
                            stack.extend([(v, c.1), a].iter().cloned());
                        } else if stt.height[b.0] <= stt.height[a.0] {
                            stack.truncate(len - 2);
                            let v = stt.append_inner(b.0, a.0, a.1, STTLabel::Compress);
                            stack.push((v, b.1));
                        } else {
                            break;
                        }
                    }
                    pos = u;
                }
                while stack.len() >= 2 {
                    let a = stack.pop().unwrap();
                    let b = stack.pop().unwrap();
                    let v = stt.append_inner(b.0, a.0, a.1, STTLabel::Compress);
                    stack.push((v, b.1));
                }
                id[v] = stack.pop().unwrap().0;
            }
        }
        stt
    }
    fn append_inner(&mut self, l: usize, r: usize, e: usize, label: STTLabel) -> usize {
        let v = self.node.len();
        let mut h = 0;
        let lp = if let Some(n) = self.node.get_mut(l) {
            n.p.set(v);
            h = std::cmp::max(h, self.height[l]);
            Pointer::new(l)
        } else {
            Pointer::null()
        };
        let rp = if let Some(n) = self.node.get_mut(r) {
            n.p.set(v);
            h = std::cmp::max(h, self.height[r]);
            Pointer::new(r)
        } else {
            Pointer::null()
        };
        if self.node.get(r).is_some() {
            h += 1;
        }
        let ep = if e < self.size {
            if label == STTLabel::Vertex || label == STTLabel::AddVertex {
                self.vertex[e] = v;
            } else if label == STTLabel::AddEdge || label == STTLabel::Compress {
                self.edge[e] = v;
            } else {
                unreachable!();
            }
            Pointer::new(e)
        } else {
            Pointer::null()
        };
        self.label.push(label);
        self.node.push(STTNode::new(lp, rp, ep));
        self.height.push(h);
        v
    }
}

// ---------- begin pointer ----------
#[derive(Clone, Copy)]
pub struct Pointer(u32);

impl Pointer {
    pub fn new(v: usize) -> Self {
        Self(v as u32)
    }
    pub fn null() -> Self {
        Self(!0)
    }
    pub fn get(&self) -> Option<usize> {
        if self.0 == !0 {
            None
        } else {
            Some(self.0 as usize)
        }
    }
    pub fn is_null(&self) -> bool {
        self.get().is_none()
    }
    pub fn set(&mut self, v: usize) {
        self.0 = v as u32
    }
}

impl From<usize> for Pointer {
    fn from(x: usize) -> Self {
        Self::new(x)
    }
}

impl Default for Pointer {
    fn default() -> Self {
        Self::null()
    }
}

impl std::fmt::Debug for Pointer {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        if let Some(x) = self.get() {
            write!(f, "{}", x)
        } else {
            write!(f, "null")
        }
    }
}
// ---------- end pointer ----------
mod util {
    pub trait Join {
        fn join(self, sep: &str) -> String;
    }

    impl<T, I> Join for I
    where
        I: Iterator<Item = T>,
        T: std::fmt::Display,
    {
        fn join(self, sep: &str) -> String {
            let mut s = String::new();
            use std::fmt::*;
            for (i, v) in self.enumerate() {
                if i > 0 {
                    write!(&mut s, "{}", sep).ok();
                }
                write!(&mut s, "{}", v).ok();
            }
            s
        }
    }
}