test/verify/aoj-grl-3-b.test.cpp

• View this file on GitHub
• Last update: 2024-04-24 02:34:04+09:00
• Problem: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_3_B

Depends on

• Graph Template(グラフテンプレート) (graph/graph-template.hpp)
• Low Link(橋/関節点) (graph/others/low-link.hpp)
• template/template.hpp

Code

// competitive-verifier: PROBLEM http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_3_B

#include "../../template/template.hpp"

#include "../../graph/others/low-link.hpp"

int main() {
  int V, E;
  cin >> V >> E;
  LowLink<> g(V);
  g.read(E, 0);
  g.build();
  auto &bridge = g.bridge;
  for(auto &v : bridge) tie(v.from, v.to) = minmax({v.from, v.to});
  sort(bridge.begin(), bridge.end(), [](auto &p, auto &q) { return tie(p.from, p.to) < tie(q.from, q.to); });
  for(auto &v : bridge) cout << v.from << " " << v.to << "\n";
}

#line 1 "test/verify/aoj-grl-3-b.test.cpp"
// competitive-verifier: PROBLEM http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_3_B

#line 1 "template/template.hpp"
#include<bits/stdc++.h>

using namespace std;

using int64 = long long;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  explicit FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};
 
template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}
#line 4 "test/verify/aoj-grl-3-b.test.cpp"

#line 2 "graph/others/low-link.hpp"

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

/**
 * @brief Graph Template(グラフテンプレート)
 */
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 {
  vector< vector< Edge< T > > > g;
  int es;

  Graph() = default;

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

  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;
      cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if(weighted) cin >> c;
      if(directed) add_directed_edge(a, b, c);
      else add_edge(a, b, c);
    }
  }

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

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

template< typename T = int >
using Edges = vector< Edge< T > >;
#line 4 "graph/others/low-link.hpp"

/**
 * @brief Low Link(橋/関節点)
 * @see http://kagamiz.hatenablog.com/entry/2013/10/05/005213
 * 
 */
template< typename T = int >
struct LowLink : Graph< T > {
public:
  using Graph< T >::Graph;
  vector< int > ord, low, articulation;
  vector< Edge< T > > bridge;
  using Graph< T >::g;

  virtual void build() {
    used.assign(g.size(), 0);
    ord.assign(g.size(), 0);
    low.assign(g.size(), 0);
    int k = 0;
    for(int i = 0; i < (int) g.size(); i++) {
      if(!used[i]) k = dfs(i, k, -1);
    }
  }

  explicit LowLink(const Graph< T > &g) : Graph< T >(g) {}

private:
  vector< int > used;

  int dfs(int idx, int k, int par) {
    used[idx] = true;
    ord[idx] = k++;
    low[idx] = ord[idx];
    bool is_articulation = false, beet = false;
    int cnt = 0;
    for(auto &to : g[idx]) {
      if(to == par && !exchange(beet, true)) {
        continue;
      }
      if(!used[to]) {
        ++cnt;
        k = dfs(to, k, idx);
        low[idx] = min(low[idx], low[to]);
        is_articulation |= par >= 0 && low[to] >= ord[idx];
        if(ord[idx] < low[to]) bridge.emplace_back(to);
      } else {
        low[idx] = min(low[idx], ord[to]);
      }
    }
    is_articulation |= par == -1 && cnt > 1;
    if(is_articulation) articulation.push_back(idx);
    return k;
  }
};
#line 6 "test/verify/aoj-grl-3-b.test.cpp"

int main() {
  int V, E;
  cin >> V >> E;
  LowLink<> g(V);
  g.read(E, 0);
  g.build();
  auto &bridge = g.bridge;
  for(auto &v : bridge) tie(v.from, v.to) = minmax({v.from, v.to});
  sort(bridge.begin(), bridge.end(), [](auto &p, auto &q) { return tie(p.from, p.to) < tie(q.from, q.to); });
  for(auto &v : bridge) cout << v.from << " " << v.to << "\n";
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	00_small_00.in	AC	6 ms	4 MB
g++	00_small_01.in	AC	6 ms	4 MB
g++	00_small_02.in	AC	6 ms	4 MB
g++	00_small_03.in	AC	6 ms	4 MB
g++	00_small_04.in	AC	6 ms	4 MB
g++	00_small_05.in	AC	6 ms	4 MB
g++	01_critical_00.in	AC	6 ms	4 MB
g++	01_critical_01.in	AC	6 ms	4 MB
g++	01_critical_02.in	AC	6 ms	4 MB
g++	01_critical_03.in	AC	6 ms	4 MB
g++	01_critical_04.in	AC	6 ms	4 MB
g++	01_critical_05.in	AC	6 ms	4 MB
g++	01_critical_06.in	AC	6 ms	4 MB
g++	01_critical_07.in	AC	6 ms	4 MB
g++	01_critical_08.in	AC	6 ms	4 MB
g++	01_critical_09.in	AC	6 ms	4 MB
g++	01_critical_10.in	AC	6 ms	4 MB
g++	01_critical_11.in	AC	6 ms	4 MB
g++	01_critical_12.in	AC	6 ms	4 MB
g++	02_grid_00.in	AC	6 ms	4 MB
g++	02_grid_01.in	AC	6 ms	4 MB
g++	02_grid_02.in	AC	6 ms	4 MB
g++	03_rand_00.in	AC	5 ms	4 MB
g++	03_rand_01.in	AC	6 ms	4 MB
g++	03_rand_02.in	AC	6 ms	4 MB
g++	03_rand_03.in	AC	6 ms	4 MB
g++	03_rand_04.in	AC	6 ms	4 MB
g++	03_rand_05.in	AC	6 ms	4 MB
g++	03_rand_06.in	AC	6 ms	4 MB
g++	03_rand_07.in	AC	6 ms	4 MB
g++	03_rand_08.in	AC	6 ms	4 MB
g++	03_rand_09.in	AC	6 ms	4 MB
g++	03_rand_10.in	AC	6 ms	4 MB
g++	03_rand_11.in	AC	7 ms	4 MB
g++	04_linear_00.in	AC	6 ms	4 MB
g++	04_linear_01.in	AC	6 ms	4 MB
g++	04_linear_02.in	AC	8 ms	5 MB
g++	04_linear_03.in	AC	9 ms	5 MB
g++	05_maximum_00.in	AC	13 ms	6 MB
g++	05_maximum_01.in	AC	16 ms	7 MB
clang++	00_small_00.in	AC	6 ms	4 MB
clang++	00_small_01.in	AC	6 ms	4 MB
clang++	00_small_02.in	AC	6 ms	4 MB
clang++	00_small_03.in	AC	6 ms	4 MB
clang++	00_small_04.in	AC	6 ms	4 MB
clang++	00_small_05.in	AC	6 ms	4 MB
clang++	01_critical_00.in	AC	6 ms	4 MB
clang++	01_critical_01.in	AC	6 ms	4 MB
clang++	01_critical_02.in	AC	6 ms	4 MB
clang++	01_critical_03.in	AC	6 ms	4 MB
clang++	01_critical_04.in	AC	6 ms	4 MB
clang++	01_critical_05.in	AC	6 ms	4 MB
clang++	01_critical_06.in	AC	6 ms	4 MB
clang++	01_critical_07.in	AC	6 ms	4 MB
clang++	01_critical_08.in	AC	6 ms	4 MB
clang++	01_critical_09.in	AC	6 ms	4 MB
clang++	01_critical_10.in	AC	6 ms	4 MB
clang++	01_critical_11.in	AC	6 ms	4 MB
clang++	01_critical_12.in	AC	6 ms	4 MB
clang++	02_grid_00.in	AC	6 ms	4 MB
clang++	02_grid_01.in	AC	6 ms	4 MB
clang++	02_grid_02.in	AC	6 ms	4 MB
clang++	03_rand_00.in	AC	5 ms	4 MB
clang++	03_rand_01.in	AC	6 ms	4 MB
clang++	03_rand_02.in	AC	6 ms	4 MB
clang++	03_rand_03.in	AC	6 ms	4 MB
clang++	03_rand_04.in	AC	6 ms	4 MB
clang++	03_rand_05.in	AC	6 ms	4 MB
clang++	03_rand_06.in	AC	6 ms	4 MB
clang++	03_rand_07.in	AC	6 ms	4 MB
clang++	03_rand_08.in	AC	6 ms	4 MB
clang++	03_rand_09.in	AC	6 ms	4 MB
clang++	03_rand_10.in	AC	6 ms	4 MB
clang++	03_rand_11.in	AC	7 ms	4 MB
clang++	04_linear_00.in	AC	6 ms	4 MB
clang++	04_linear_01.in	AC	6 ms	4 MB
clang++	04_linear_02.in	AC	8 ms	5 MB
clang++	04_linear_03.in	AC	9 ms	5 MB
clang++	05_maximum_00.in	AC	13 ms	6 MB
clang++	05_maximum_01.in	AC	15 ms	7 MB

Back to top page