test/verify/yosupo-dominatortree.test.cpp

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Last update: 2026-08-10 14:32:04+00:00
Problem: https://judge.yosupo.jp/problem/dominatortree

Depends on

Code

// clang-format off
// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/dominatortree
// clang-format on

#include <iostream>

#include "../../graph/others/dominator-tree.hpp"

using namespace std;

int main() {
  int N, M, S;
  cin >> N >> M >> S;
  DominatorTree<> g(N);
  g.read(M, 0, false, true);
  g.build(S);
  for (int i = 0; i < N; i++) cout << g[i] << " ";
  cout << endl;
}

#line 1 "test/verify/yosupo-dominatortree.test.cpp"
// clang-format off
// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/dominatortree
// clang-format on

#include <iostream>

#line 2 "graph/others/dominator-tree.hpp"

#include <iterator>
#include <numeric>
#include <vector>

#line 2 "graph/graph-template.hpp"

#include <cstddef>
#line 6 "graph/graph-template.hpp"

template <typename T = int>
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1)
      : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template <typename T = int>
struct Graph {
  std::vector<std::vector<Edge<T> > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  std::size_t size() const { return g.size(); }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false,
            bool directed = false) {
    for (int i = 0; i < M; i++) {
      int a, b;
      std::cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if (weighted) std::cin >> c;
      if (directed)
        add_directed_edge(a, b, c);
      else
        add_edge(a, b, c);
    }
  }

  inline std::vector<Edge<T> >& operator[](const int& k) { return g[k]; }

  inline const std::vector<Edge<T> >& operator[](const int& k) const {
    return g[k];
  }
};

template <typename T = int>
using Edges = std::vector<Edge<T> >;
#line 8 "graph/others/dominator-tree.hpp"

/**
 * @brief Dominator Tree
 *
 * @see http://sigma425.hatenablog.com/entry/2015/12/25/224053
 */
template <typename T = int>
struct DominatorTree : Graph<T> {
 public:
  using Graph<T>::Graph;
  using Graph<T>::g;

  void build(int root) {
    rg = Graph<T>(g.size());
    par.assign(g.size(), 0);
    idom.assign(g.size(), -1);
    semi.assign(g.size(), -1);
    ord.reserve(g.size());
    UnionFind uf(semi);

    const int N = (int)g.size();
    dfs(root);
    for (int i = 0; i < N; i++) {
      for (auto& to : g[i]) {
        if (~semi[i]) rg.add_directed_edge(to, i);
      }
    }

    std::vector<std::vector<int> > bucket(N);
    std::vector<int> U(N);
    for (int i = (int)ord.size() - 1; i >= 0; i--) {
      int x = ord[i];
      for (int v : rg[x]) {
        v = uf.eval(v);
        if (semi[x] > semi[v]) semi[x] = semi[v];
      }
      bucket[ord[semi[x]]].emplace_back(x);
      for (int v : bucket[par[x]]) U[v] = uf.eval(v);
      bucket[par[x]].clear();
      uf.link(par[x], x);
    }
    for (int i = 1; i < (int)ord.size(); i++) {
      int x = ord[i], u = U[x];
      idom[x] = semi[x] == semi[u] ? semi[x] : idom[u];
    }
    for (int i = 1; i < (int)ord.size(); i++) {
      int x = ord[i];
      idom[x] = ord[idom[x]];
    }
    idom[root] = root;
  }

  int operator[](const int& k) const { return idom[k]; }

 private:
  Graph<T> rg;

  struct UnionFind {
    const std::vector<int>& semi;
    std::vector<int> par, m;

    explicit UnionFind(const std::vector<int>& semi)
        : semi(semi), par(semi.size()), m(semi.size()) {
      std::iota(std::begin(par), std::end(par), 0);
      std::iota(std::begin(m), std::end(m), 0);
    }

    int find(int v) {
      if (par[v] == v) return v;
      int r = find(par[v]);
      if (semi[m[v]] > semi[m[par[v]]]) m[v] = m[par[v]];
      return par[v] = r;
    }

    int eval(int v) {
      find(v);
      return m[v];
    }

    void link(int p, int c) { par[c] = p; }
  };

  std::vector<int> ord, par;
  std::vector<int> idom, semi;

  void dfs(int idx) {
    semi[idx] = (int)ord.size();
    ord.emplace_back(idx);
    for (auto& to : g[idx]) {
      if (~semi[to]) continue;
      dfs(to);
      par[to] = idx;
    }
  }
};
#line 8 "test/verify/yosupo-dominatortree.test.cpp"

using namespace std;

int main() {
  int N, M, S;
  cin >> N >> M >> S;
  DominatorTree<> g(N);
  g.read(M, 0, false, true);
  g.build(S);
  for (int i = 0; i < N; i++) cout << g[i] << " ";
  cout << endl;
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	example_00	AC	2 ms	4 MB
g++	example_01	AC	2 ms	4 MB
g++	gen_tree_00	AC	134 ms	24 MB
g++	gen_tree_01	AC	135 ms	24 MB
g++	gen_tree_02	AC	134 ms	24 MB
g++	gen_tree_2_00	AC	146 ms	26 MB
g++	gen_tree_2_01	AC	148 ms	26 MB
g++	gen_tree_2_02	AC	147 ms	26 MB
g++	random_00	AC	22 ms	16 MB
g++	random_01	AC	83 ms	21 MB
g++	random_02	AC	19 ms	9 MB
g++	random_03	AC	29 ms	20 MB
g++	random_04	AC	4 ms	5 MB
clang++	example_00	AC	2 ms	4 MB
clang++	example_01	AC	2 ms	4 MB
clang++	gen_tree_00	AC	136 ms	24 MB
clang++	gen_tree_01	AC	137 ms	24 MB
clang++	gen_tree_02	AC	131 ms	25 MB
clang++	gen_tree_2_00	AC	146 ms	27 MB
clang++	gen_tree_2_01	AC	142 ms	27 MB
clang++	gen_tree_2_02	AC	148 ms	27 MB
clang++	random_00	AC	23 ms	16 MB
clang++	random_01	AC	85 ms	21 MB
clang++	random_02	AC	19 ms	9 MB
clang++	random_03	AC	30 ms	20 MB
clang++	random_04	AC	4 ms	5 MB