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dynamic_tree_path_affine_sum.hpp

SECTIONGraph INCLUDEnoya/graph/dynamic_tree_path_affine_sum.hpp

固定树上修改点值或边的仿射函数,查询任意根收到的所有点路径变换值之和。

Complexity: Time: \(O(n \log n)\) construction and \(O(\log n)\) amortized per vertex update, edge update, or root query. Space: \(O(n)\).

Source: Nyaan (path aggregation)

AC 记录:point_set_tree_path_composite_sum, point_set_tree_path_composite_sum_fixed_root。

跳到代码 · GitHub ↗

Implementation

当前头文件,省略 include guard;依赖见 #include。

/// @complexity Time: O(n log n) construction and O(log n) amortized per
/// vertex update, edge update, or root query. Space: O(n).

#include "noya/graph/dynamic_rerooting_top_tree.hpp"

#include <algorithm>
#include <cassert>
#include <utility>
#include <vector>

namespace noya {

namespace dynamic_tree_path_affine_sum_internal {

template <class Mint> struct traits {
  struct path {
    Mint mul{};
    Mint add{};
    Mint sum{};
    Mint cnt{};
  };
  struct point {
    Mint sum{};
    Mint cnt{};
  };
  struct info {
    bool iv = true;
    Mint a{};
    Mint b{};
  };

  static path vertex(const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), x.a, Mint(1)};
    }
    return {x.a, x.b, Mint(0), Mint(0)};
  }

  static path compress(const path &fa, const path &v) {
    return {fa.mul * v.mul, fa.mul * v.add + fa.add,
            fa.sum + fa.mul * v.sum + fa.add * v.cnt, fa.cnt + v.cnt};
  }

  static point rake(const point &a, const point &b) {
    return {a.sum + b.sum, a.cnt + b.cnt};
  }

  static point add_edge(const path &cl) { return {cl.sum, cl.cnt}; }

  static path add_vertex(const point &ch, const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), ch.sum + x.a, ch.cnt + Mint(1)};
    }
    return {x.a, x.b, ch.sum * x.a + ch.cnt * x.b, ch.cnt};
  }
};

} // namespace dynamic_tree_path_affine_sum_internal

/// @brief Maintain sums of edge-affine transforms from any chosen root.
/// Every original edge is split by an edge-node carrying its affine map. A top
/// tree cluster stores the affine transform along its boundary path, the sum
/// of all values entering that path, and their count. Compress composes paths;
/// rake adds independent branches. Preferred-path expose therefore propagates
/// a point update to the complete rerooted aggregate in logarithmic time.
/// The topology is a fixed nonempty tree; ee[e] and aff[e] describe the same
/// undirected edge, with the same map in either direction. query(r) sums, over
/// all v, val[v] transformed along v -> r (the map nearest r is outermost).
/// Supports vertex-value assignments and edge-map assignments, not link/cut.
/// Mint is a commutative semiring with default zero, construction from 0/1,
/// copy, + and *; no comparison, subtraction or division is needed. Counts
/// are stored in Mint too. Complexity assumes constant-time Mint operations.
/// All node/edge indices and 2*n-1 must fit int; inputs must describe a tree.
/// Copies share the same forest, including updates; they are not deep copies.
template <class Mint> class dynamic_tree_path_affine_sum {
  using trait = dynamic_tree_path_affine_sum_internal::traits<Mint>;
  using path = typename trait::path;
  using point = typename trait::point;
  using info = typename trait::info;
  using dp_type =
      dynamic_rerooting_dp<path, point, info, trait::vertex, trait::compress,
                           trait::rake, trait::add_edge, trait::add_vertex>;

  int n;
  dp_type dp;

  static std::vector<info>
  make_info(const std::vector<Mint> &val,
            const std::vector<std::pair<Mint, Mint>> &aff) {
    std::vector<info> res(val.size() + aff.size());
    for (int u = 0; u < int(val.size()); u++) {
      res[u] = {true, val[u], Mint(0)};
    }
    for (int e = 0; e < int(aff.size()); e++) {
      res[val.size() + e] = {false, aff[e].first, aff[e].second};
    }
    return res;
  }

public:
  dynamic_tree_path_affine_sum(const std::vector<Mint> &val,
                               const std::vector<std::pair<int, int>> &ee,
                               const std::vector<std::pair<Mint, Mint>> &aff)
      : n(int(val.size())), dp(make_info(val, aff)) {
    assert(n >= 1);
    assert(int(ee.size()) == n - 1);
    assert(aff.size() == ee.size());
    for (int e = 0; e < n - 1; e++) {
      auto [a, b] = ee[e];
      assert(0 <= a && a < n && 0 <= b && b < n);
      dp.link(n + e, a);
      dp.link(n + e, b);
    }
  }

  void set_vertex(int u, Mint va1) {
    assert(0 <= u && u < n);
    dp.set_info(u, {true, va1, Mint(0)});
  }

  void set_edge(int e, Mint mul, Mint add) {
    assert(0 <= e && e < n - 1);
    dp.set_info(n + e, {false, mul, add});
  }

  Mint query(int rt) {
    assert(0 <= rt && rt < n);
    return dp.query(rt).sum;
  }
};

} // namespace noya

 // NOYA_DYNAMIC_TREE_PATH_AFFINE_SUM_HPP
#ifndef NOYA_DYNAMIC_TREE_PATH_AFFINE_SUM_HPP
#define NOYA_DYNAMIC_TREE_PATH_AFFINE_SUM_HPP 1

/// @complexity Time: O(n log n) construction and O(log n) amortized per
/// vertex update, edge update, or root query. Space: O(n).

#include "noya/graph/dynamic_rerooting_top_tree.hpp"

#include <algorithm>
#include <cassert>
#include <utility>
#include <vector>

namespace noya {

namespace dynamic_tree_path_affine_sum_internal {

template <class Mint> struct traits {
  struct path {
    Mint mul{};
    Mint add{};
    Mint sum{};
    Mint cnt{};
  };
  struct point {
    Mint sum{};
    Mint cnt{};
  };
  struct info {
    bool iv = true;
    Mint a{};
    Mint b{};
  };

  static path vertex(const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), x.a, Mint(1)};
    }
    return {x.a, x.b, Mint(0), Mint(0)};
  }

  static path compress(const path &fa, const path &v) {
    return {fa.mul * v.mul, fa.mul * v.add + fa.add,
            fa.sum + fa.mul * v.sum + fa.add * v.cnt, fa.cnt + v.cnt};
  }

  static point rake(const point &a, const point &b) {
    return {a.sum + b.sum, a.cnt + b.cnt};
  }

  static point add_edge(const path &cl) { return {cl.sum, cl.cnt}; }

  static path add_vertex(const point &ch, const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), ch.sum + x.a, ch.cnt + Mint(1)};
    }
    return {x.a, x.b, ch.sum * x.a + ch.cnt * x.b, ch.cnt};
  }
};

} // namespace dynamic_tree_path_affine_sum_internal

/// @brief Maintain sums of edge-affine transforms from any chosen root.
/// Every original edge is split by an edge-node carrying its affine map. A top
/// tree cluster stores the affine transform along its boundary path, the sum
/// of all values entering that path, and their count. Compress composes paths;
/// rake adds independent branches. Preferred-path expose therefore propagates
/// a point update to the complete rerooted aggregate in logarithmic time.
/// The topology is a fixed nonempty tree; ee[e] and aff[e] describe the same
/// undirected edge, with the same map in either direction. query(r) sums, over
/// all v, val[v] transformed along v -> r (the map nearest r is outermost).
/// Supports vertex-value assignments and edge-map assignments, not link/cut.
/// Mint is a commutative semiring with default zero, construction from 0/1,
/// copy, + and *; no comparison, subtraction or division is needed. Counts
/// are stored in Mint too. Complexity assumes constant-time Mint operations.
/// All node/edge indices and 2*n-1 must fit int; inputs must describe a tree.
/// Copies share the same forest, including updates; they are not deep copies.
template <class Mint> class dynamic_tree_path_affine_sum {
  using trait = dynamic_tree_path_affine_sum_internal::traits<Mint>;
  using path = typename trait::path;
  using point = typename trait::point;
  using info = typename trait::info;
  using dp_type =
      dynamic_rerooting_dp<path, point, info, trait::vertex, trait::compress,
                           trait::rake, trait::add_edge, trait::add_vertex>;

  int n;
  dp_type dp;

  static std::vector<info>
  make_info(const std::vector<Mint> &val,
            const std::vector<std::pair<Mint, Mint>> &aff) {
    std::vector<info> res(val.size() + aff.size());
    for (int u = 0; u < int(val.size()); u++) {
      res[u] = {true, val[u], Mint(0)};
    }
    for (int e = 0; e < int(aff.size()); e++) {
      res[val.size() + e] = {false, aff[e].first, aff[e].second};
    }
    return res;
  }

public:
  dynamic_tree_path_affine_sum(const std::vector<Mint> &val,
                               const std::vector<std::pair<int, int>> &ee,
                               const std::vector<std::pair<Mint, Mint>> &aff)
      : n(int(val.size())), dp(make_info(val, aff)) {
    assert(n >= 1);
    assert(int(ee.size()) == n - 1);
    assert(aff.size() == ee.size());
    for (int e = 0; e < n - 1; e++) {
      auto [a, b] = ee[e];
      assert(0 <= a && a < n && 0 <= b && b < n);
      dp.link(n + e, a);
      dp.link(n + e, b);
    }
  }

  void set_vertex(int u, Mint va1) {
    assert(0 <= u && u < n);
    dp.set_info(u, {true, va1, Mint(0)});
  }

  void set_edge(int e, Mint mul, Mint add) {
    assert(0 <= e && e < n - 1);
    dp.set_info(n + e, {false, mul, add});
  }

  Mint query(int rt) {
    assert(0 <= rt && rt < n);
    return dp.query(rt).sum;
  }
};

} // namespace noya

#endif // NOYA_DYNAMIC_TREE_PATH_AFFINE_SUM_HPP
/// @complexity Time: O(n log n) construction and O(log n) amortized per
/// vertex update, edge update, or root query. Space: O(n).

/// @complexity Time: O(log n) amortized per link, cut, point update, reroot,
/// or aggregate query, for O(1) DP operations. Releasing the last owner is O(n).
/// Space: O(n), including recycled nodes.

#include <algorithm>
#include <cassert>
#include <cstddef>
#include <deque>
#include <limits>
#include <memory>
#include <utility>
#include <vector>

namespace noya {

namespace dynamic_rerooting_internal {

template <class Point, auto rk> class dashed_splay_tree {
public:
  struct node {
    node *l = nullptr;
    node *r = nullptr;
    node *fa = nullptr;
    Point key;
    Point sum;

    explicit node(const Point &val) : key(val), sum(val) {}
  };
  using node_pointer = node *;

private:
  std::deque<node> nodes;
  std::vector<node_pointer> free;

  node_pointer allocate(const Point &val) {
    if (free.empty()) {
      nodes.emplace_back(val);
      return &nodes.back();
    }
    node_pointer cur = free.back();
    free.pop_back();
    cur->l = cur->r = cur->fa = nullptr;
    cur->key = cur->sum = val;
    return cur;
  }

  static void update(node_pointer cur) {
    cur->sum = cur->key;
    if (cur->l) {
      cur->sum = rk(cur->sum, cur->l->sum);
    }
    if (cur->r) {
      cur->sum = rk(cur->sum, cur->r->sum);
    }
  }

  static void rotate_right(node_pointer cur) {
    node_pointer fa = cur->fa;
    node_pointer gf = fa->fa;
    fa->l = cur->r;
    if (cur->r) {
      cur->r->fa = fa;
    }
    cur->r = fa;
    fa->fa = cur;
    update(fa);
    cur->fa = gf;
    if (gf) {
      if (gf->l == fa) {
        gf->l = cur;
      }
      if (gf->r == fa) {
        gf->r = cur;
      }
    }
  }

  static void rotate_left(node_pointer cur) {
    node_pointer fa = cur->fa;
    node_pointer gf = fa->fa;
    fa->r = cur->l;
    if (cur->l) {
      cur->l->fa = fa;
    }
    cur->l = fa;
    fa->fa = cur;
    update(fa);
    cur->fa = gf;
    if (gf) {
      if (gf->l == fa) {
        gf->l = cur;
      }
      if (gf->r == fa) {
        gf->r = cur;
      }
    }
  }

  static node_pointer rightmost(node_pointer cur) {
    while (cur->r) {
      cur = cur->r;
    }
    return cur;
  }

public:
  static void splay(node_pointer cur) {
    if (!cur->fa) {
      return;
    }
    while (cur->fa) {
      node_pointer fa = cur->fa;
      if (!fa->fa) {
        if (fa->l == cur) {
          rotate_right(cur);
        } else {
          rotate_left(cur);
        }
      } else {
        node_pointer gf = fa->fa;
        if (gf->l == fa) {
          if (fa->l == cur) {
            rotate_right(fa);
            rotate_right(cur);
          } else {
            rotate_left(cur);
            rotate_right(cur);
          }
        } else if (fa->r == cur) {
          rotate_left(fa);
          rotate_left(cur);
        } else {
          rotate_right(cur);
          rotate_left(cur);
        }
      }
    }
    update(cur);
  }

  node_pointer insert(node_pointer rt, const Point &val) {
    node_pointer ins = allocate(val);
    // Rake is commutative: the previous tree can become the new root's left
    // child directly, without searching for and splaying its rightmost node.
    ins->l = rt;
    if (rt) {
      rt->fa = ins;
      update(ins);
    }
    return ins;
  }

  node_pointer erase(node_pointer cur) {
    splay(cur);
    node_pointer l = cur->l;
    node_pointer r = cur->r;
    free.push_back(cur);
    if (!l) {
      if (r) {
        r->fa = nullptr;
      }
      return r;
    }
    if (!r) {
      l->fa = nullptr;
      return l;
    }
    l->fa = nullptr;
    node_pointer rt = rightmost(l);
    splay(rt);
    rt->r = r;
    r->fa = rt;
    update(rt);
    return rt;
  }
};

} // namespace dynamic_rerooting_internal

/// @brief Dynamic rerooting DP on a top tree represented by preferred paths.
/// `cmp` joins consecutive path clusters, while commutative `rk`
/// combines light subtrees. `ae` changes a path cluster into a point
/// cluster and `av` attaches all light clusters to one path vertex.
/// Expose moves preferred edges between the path splay and the dashed-edge
/// splay, so both forward and reversed path aggregates stay current.
/// DP operations must obey the path/rake composition laws and be pure.
/// Copies share the same forest. Stable node handles are owned by that shared
/// storage; do not delete them or use them after the last owner is released.
/// Link different components with v as a represented root; cut a nonroot.
template <class Path, class Point, class Info, auto vtx, auto cmp, auto rk,
          auto ae, auto av>
class dynamic_rerooting_top_tree {
  using dashed_tree = dynamic_rerooting_internal::dashed_splay_tree<Point, rk>;

  struct node {
    node *l = nullptr;
    node *r = nullptr;
    node *fa = nullptr;
    Info inf;
    Path key{};
    Path fwd{};
    Path bwd{};
    typename dashed_tree::node_pointer lt = nullptr;
    typename dashed_tree::node_pointer lp = nullptr;
    bool rev = false;

    explicit node(const Info &val) : inf(val) {}

    bool is_auxiliary_root() const {
      return !fa || (fa->l != this && fa->r != this);
    }
  };

  struct storage {
    std::deque<node> vertices;
    dashed_tree dashed;
  };
  std::shared_ptr<storage> owner = std::make_shared<storage>();

public:
  using node_pointer = node *;

private:
  static void toggle(node_pointer cur) {
    std::swap(cur->l, cur->r);
    std::swap(cur->fwd, cur->bwd);
    cur->rev ^= true;
  }

  static void push(node_pointer cur) {
    if (!cur->rev) {
      return;
    }
    if (cur->l) {
      toggle(cur->l);
    }
    if (cur->r) {
      toggle(cur->r);
    }
    cur->rev = false;
  }

  static void pull(node_pointer cur) {
    Path fwd = cur->key;
    Path bwd = cur->key;
    if (cur->l) {
      fwd = cmp(cur->l->fwd, fwd);
      bwd = cmp(bwd, cur->l->bwd);
    }
    if (cur->r) {
      fwd = cmp(fwd, cur->r->fwd);
      bwd = cmp(cur->r->bwd, bwd);
    }
    cur->fwd = fwd;
    cur->bwd = bwd;
  }

  static void update(node_pointer cur) {
    cur->key = cur->lt ? av(cur->lt->sum, cur->inf) : vtx(cur->inf);
    pull(cur);
  }

  static void rotate_right(node_pointer cur) {
    node_pointer fa = cur->fa;
    node_pointer gf = fa->fa;
    if (fa->is_auxiliary_root()) {
      cur->lp = fa->lp;
      fa->lp = nullptr;
    }
    push(fa);
    push(cur);
    fa->l = cur->r;
    if (cur->r) {
      cur->r->fa = fa;
    }
    cur->r = fa;
    fa->fa = cur;
    pull(fa);
    cur->fa = gf;
    if (gf) {
      if (gf->l == fa) {
        gf->l = cur;
      }
      if (gf->r == fa) {
        gf->r = cur;
      }
    }
  }

  static void rotate_left(node_pointer cur) {
    node_pointer fa = cur->fa;
    node_pointer gf = fa->fa;
    if (fa->is_auxiliary_root()) {
      cur->lp = fa->lp;
      fa->lp = nullptr;
    }
    push(fa);
    push(cur);
    fa->r = cur->l;
    if (cur->l) {
      cur->l->fa = fa;
    }
    cur->l = fa;
    fa->fa = cur;
    pull(fa);
    cur->fa = gf;
    if (gf) {
      if (gf->l == fa) {
        gf->l = cur;
      }
      if (gf->r == fa) {
        gf->r = cur;
      }
    }
  }

  static void splay(node_pointer cur) {
    push(cur);
    if (cur->is_auxiliary_root()) {
      return;
    }
    while (!cur->is_auxiliary_root()) {
      node_pointer fa = cur->fa;
      if (fa->is_auxiliary_root()) {
        push(fa);
        push(cur);
        if (fa->l == cur) {
          rotate_right(cur);
        } else {
          rotate_left(cur);
        }
      } else {
        node_pointer gf = fa->fa;
        push(gf);
        push(fa);
        push(cur);
        if (gf->l == fa) {
          if (fa->l == cur) {
            rotate_right(fa);
            rotate_right(cur);
          } else {
            rotate_left(cur);
            rotate_right(cur);
          }
        } else if (fa->r == cur) {
          rotate_left(fa);
          rotate_left(cur);
        } else {
          rotate_right(cur);
          rotate_left(cur);
        }
      }
    }
    pull(cur);
  }

  node_pointer expose(node_pointer cur) {
    node_pointer pre = nullptr;
    for (node_pointer anc = cur; anc; anc = anc->fa) {
      splay(anc);
      if (anc->r) {
        anc->lt = owner->dashed.insert(anc->lt, ae(anc->r->fwd));
        anc->r->lp = anc->lt;
      }
      anc->r = pre;
      if (pre) {
        push(pre);
        anc->lt = owner->dashed.erase(pre->lp);
        pre->lp = nullptr;
      }
      update(anc);
      pre = anc;
    }
    splay(cur);
    return pre;
  }

public:
  node_pointer make_node(const Info &inf) {
    if (!owner) {
      owner = std::make_shared<storage>();
    }
    owner->vertices.emplace_back(inf);
    node_pointer res = &owner->vertices.back();
    update(res);
    return res;
  }

  void evert(node_pointer cur) {
    expose(cur);
    toggle(cur);
    push(cur);
  }

  void link(node_pointer v, node_pointer fa) {
    expose(fa);
    expose(v);
    v->fa = fa;
    fa->r = v;
    pull(fa);
  }

  void cut(node_pointer v) {
    expose(v);
    node_pointer fa = v->l;
    assert(fa);
    v->l = nullptr;
    fa->fa = nullptr;
    pull(v);
  }

  void set_info(node_pointer cur, const Info &inf) {
    expose(cur);
    cur->inf = inf;
    update(cur);
  }

  Info get_info(node_pointer cur) const { return cur->inf; }

  Path query(node_pointer rt) {
    evert(rt);
    return rt->fwd;
  }

  Path query_subtree(node_pointer rt, node_pointer rot) {
    evert(rt);
    expose(rot);
    // rot is the bottom of the exposed path: its cached key is precisely
    // its rooted subtree, excluding the ancestor path in rot->l.
    assert(!rot->r);
    return rot->key;
  }
};

/// @brief Index-based wrapper; copies share the same forest.
/// Vertices must be valid; link distinct components and cut an existing edge.
/// The two query_subtree vertices must belong to the same component.
template <class Path, class Point, class Info, auto vtx, auto cmp, auto rk,
          auto ae, auto av>
class dynamic_rerooting_dp {
  using top_tree_type =
      dynamic_rerooting_top_tree<Path, Point, Info, vtx, cmp, rk, ae, av>;
  top_tree_type tr;
  std::vector<typename top_tree_type::node_pointer> nd;

  void check_vertex(int u) const {
    assert(0 <= u && std::size_t(u) < nd.size());
  }

public:
  explicit dynamic_rerooting_dp(const std::vector<Info> &inf) : nd(inf.size()) {
    assert(inf.size() <= std::size_t(std::numeric_limits<int>::max()));
    for (int i = 0; i < int(inf.size()); i++) {
      nd[i] = tr.make_node(inf[i]);
    }
  }

  void link(int a, int b) {
    check_vertex(a);
    check_vertex(b);
    tr.evert(nd[a]);
    tr.link(nd[a], nd[b]);
  }

  void cut(int a, int b) {
    check_vertex(a);
    check_vertex(b);
    tr.evert(nd[a]);
    tr.cut(nd[b]);
  }

  void set_info(int idx, const Info &inf) {
    check_vertex(idx);
    tr.set_info(nd[idx], inf);
  }

  Info get_info(int idx) const {
    check_vertex(idx);
    return tr.get_info(nd[idx]);
  }

  Path query(int rt) {
    check_vertex(rt);
    return tr.query(nd[rt]);
  }

  Path query_subtree(int rt, int rot) {
    check_vertex(rt);
    check_vertex(rot);
    return tr.query_subtree(nd[rt], nd[rot]);
  }
};

} // namespace noya

#include <algorithm>
#include <cassert>
#include <utility>
#include <vector>

namespace noya {

namespace dynamic_tree_path_affine_sum_internal {

template <class Mint> struct traits {
  struct path {
    Mint mul{};
    Mint add{};
    Mint sum{};
    Mint cnt{};
  };
  struct point {
    Mint sum{};
    Mint cnt{};
  };
  struct info {
    bool iv = true;
    Mint a{};
    Mint b{};
  };

  static path vertex(const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), x.a, Mint(1)};
    }
    return {x.a, x.b, Mint(0), Mint(0)};
  }

  static path compress(const path &fa, const path &v) {
    return {fa.mul * v.mul, fa.mul * v.add + fa.add,
            fa.sum + fa.mul * v.sum + fa.add * v.cnt, fa.cnt + v.cnt};
  }

  static point rake(const point &a, const point &b) {
    return {a.sum + b.sum, a.cnt + b.cnt};
  }

  static point add_edge(const path &cl) { return {cl.sum, cl.cnt}; }

  static path add_vertex(const point &ch, const info &x) {
    if (x.iv) {
      return {Mint(1), Mint(0), ch.sum + x.a, ch.cnt + Mint(1)};
    }
    return {x.a, x.b, ch.sum * x.a + ch.cnt * x.b, ch.cnt};
  }
};

} // namespace dynamic_tree_path_affine_sum_internal

/// @brief Maintain sums of edge-affine transforms from any chosen root.
/// Every original edge is split by an edge-node carrying its affine map. A top
/// tree cluster stores the affine transform along its boundary path, the sum
/// of all values entering that path, and their count. Compress composes paths;
/// rake adds independent branches. Preferred-path expose therefore propagates
/// a point update to the complete rerooted aggregate in logarithmic time.
/// The topology is a fixed nonempty tree; ee[e] and aff[e] describe the same
/// undirected edge, with the same map in either direction. query(r) sums, over
/// all v, val[v] transformed along v -> r (the map nearest r is outermost).
/// Supports vertex-value assignments and edge-map assignments, not link/cut.
/// Mint is a commutative semiring with default zero, construction from 0/1,
/// copy, + and *; no comparison, subtraction or division is needed. Counts
/// are stored in Mint too. Complexity assumes constant-time Mint operations.
/// All node/edge indices and 2*n-1 must fit int; inputs must describe a tree.
/// Copies share the same forest, including updates; they are not deep copies.
template <class Mint> class dynamic_tree_path_affine_sum {
  using trait = dynamic_tree_path_affine_sum_internal::traits<Mint>;
  using path = typename trait::path;
  using point = typename trait::point;
  using info = typename trait::info;
  using dp_type =
      dynamic_rerooting_dp<path, point, info, trait::vertex, trait::compress,
                           trait::rake, trait::add_edge, trait::add_vertex>;

  int n;
  dp_type dp;

  static std::vector<info>
  make_info(const std::vector<Mint> &val,
            const std::vector<std::pair<Mint, Mint>> &aff) {
    std::vector<info> res(val.size() + aff.size());
    for (int u = 0; u < int(val.size()); u++) {
      res[u] = {true, val[u], Mint(0)};
    }
    for (int e = 0; e < int(aff.size()); e++) {
      res[val.size() + e] = {false, aff[e].first, aff[e].second};
    }
    return res;
  }

public:
  dynamic_tree_path_affine_sum(const std::vector<Mint> &val,
                               const std::vector<std::pair<int, int>> &ee,
                               const std::vector<std::pair<Mint, Mint>> &aff)
      : n(int(val.size())), dp(make_info(val, aff)) {
    assert(n >= 1);
    assert(int(ee.size()) == n - 1);
    assert(aff.size() == ee.size());
    for (int e = 0; e < n - 1; e++) {
      auto [a, b] = ee[e];
      assert(0 <= a && a < n && 0 <= b && b < n);
      dp.link(n + e, a);
      dp.link(n + e, b);
    }
  }

  void set_vertex(int u, Mint va1) {
    assert(0 <= u && u < n);
    dp.set_info(u, {true, va1, Mint(0)});
  }

  void set_edge(int e, Mint mul, Mint add) {
    assert(0 <= e && e < n - 1);
    dp.set_info(n + e, {false, mul, add});
  }

  Mint query(int rt) {
    assert(0 <= rt && rt < n);
    return dp.query(rt).sum;
  }
};

} // namespace noya

 // NOYA_DYNAMIC_TREE_PATH_AFFINE_SUM_HPP