test/verify/yosupo-two-edge-connected-components-2.test.cpp

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• Last update: 2024-04-27 01:27:28+09:00
• Problem: https://judge.yosupo.jp/problem/two_edge_connected_components

Depends on

• Incremental Bridge Connectivity (graph/connected-components/incremental-bridge-connectivity.hpp)
• Union Find (structure/union-find/union-find.hpp)
• template/template.hpp

Code

// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/two_edge_connected_components

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

#include "../../graph/connected-components/incremental-bridge-connectivity.hpp"

int main() {
  int n, m;
  cin >> n >> m;
  IncrementalBridgeConnectivity ibc(n);
  for(int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    ibc.add_edge(a, b);
  }
  vector< int > id(n, -1);
  int k = 0;
  vector< vector< int > > ans(n);
  for(int i = 0; i < n; i++) {
    int r = ibc.find(i);
    if(id[r] == -1) {
      id[r] = k;
      k += 1;
    }
    ans[id[r]].push_back(i);
  }
  cout << k << "\n";
  for(int i = 0; i < k; i++) {
    cout << ans[i].size() << " " << ans[i] << "\n";
  }
}

#line 1 "test/verify/yosupo-two-edge-connected-components-2.test.cpp"
// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/two_edge_connected_components

#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/yosupo-two-edge-connected-components-2.test.cpp"

#line 2 "graph/connected-components/incremental-bridge-connectivity.hpp"

#line 2 "structure/union-find/union-find.hpp"

struct UnionFind {
  vector<int> data;

  UnionFind() = default;

  explicit UnionFind(size_t sz) : data(sz, -1) {}

  bool unite(int x, int y) {
    x = find(x), y = find(y);
    if (x == y) return false;
    if (data[x] > data[y]) swap(x, y);
    data[x] += data[y];
    data[y] = x;
    return true;
  }

  int find(int k) {
    if (data[k] < 0) return (k);
    return data[k] = find(data[k]);
  }

  int size(int k) { return -data[find(k)]; }

  bool same(int x, int y) { return find(x) == find(y); }

  vector<vector<int> > groups() {
    int n = (int)data.size();
    vector<vector<int> > ret(n);
    for (int i = 0; i < n; i++) {
      ret[find(i)].emplace_back(i);
    }
    ret.erase(remove_if(begin(ret), end(ret),
                        [&](const vector<int> &v) { return v.empty(); }),
              end(ret));
    return ret;
  }
};
#line 4 "graph/connected-components/incremental-bridge-connectivity.hpp"

struct IncrementalBridgeConnectivity {
 private:
  UnionFind cc, bcc;
  vector<int> bbf;
  size_t bridge;

  int size() { return bbf.size(); }

  int par(int x) { return bbf[x] == size() ? size() : bcc.find(bbf[x]); }

  int lca(int x, int y) {
    unordered_set<int> used;
    for (;;) {
      if (x != size()) {
        if (!used.insert(x).second) return x;
        x = par(x);
      }
      swap(x, y);
    }
  }

  void compress(int x, int y) {
    while (bcc.find(x) != bcc.find(y)) {
      int nxt = par(x);
      bbf[x] = bbf[y];
      bcc.unite(x, y);
      x = nxt;
      --bridge;
    }
  }

  void link(int x, int y) {
    int v = x, pre = y;
    while (v != size()) {
      int nxt = par(v);
      bbf[v] = pre;
      pre = v;
      v = nxt;
    }
  }

 public:
  IncrementalBridgeConnectivity() = default;

  explicit IncrementalBridgeConnectivity(int sz)
      : cc(sz), bcc(sz), bbf(sz, sz), bridge(0) {}

  int find(int k) { return bcc.find(k); }

  size_t bridge_size() const { return bridge; }

  void add_edge(int x, int y) {
    x = bcc.find(x);
    y = bcc.find(y);
    if (cc.find(x) == cc.find(y)) {
      int w = lca(x, y);
      compress(x, w);
      compress(y, w);
    } else {
      if (cc.size(x) > cc.size(y)) swap(x, y);
      link(x, y);
      cc.unite(x, y);
      ++bridge;
    }
  }
};
#line 6 "test/verify/yosupo-two-edge-connected-components-2.test.cpp"

int main() {
  int n, m;
  cin >> n >> m;
  IncrementalBridgeConnectivity ibc(n);
  for(int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    ibc.add_edge(a, b);
  }
  vector< int > id(n, -1);
  int k = 0;
  vector< vector< int > > ans(n);
  for(int i = 0; i < n; i++) {
    int r = ibc.find(i);
    if(id[r] == -1) {
      id[r] = k;
      k += 1;
    }
    ans[id[r]].push_back(i);
  }
  cout << k << "\n";
  for(int i = 0; i < k; i++) {
    cout << ans[i].size() << " " << ans[i] << "\n";
  }
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	example_00	AC	6 ms	4 MB
g++	example_01	AC	6 ms	4 MB
g++	example_02	AC	6 ms	4 MB
g++	large_cycle_00	AC	42 ms	10 MB
g++	max_random_00	AC	71 ms	15 MB
g++	max_random_01	AC	71 ms	15 MB
g++	max_random_02	AC	68 ms	15 MB
g++	random_1_00	AC	49 ms	10 MB
g++	random_1_01	AC	54 ms	12 MB
g++	random_1_02	AC	33 ms	6 MB
g++	random_2_00	AC	21 ms	4 MB
g++	random_2_01	AC	9 ms	4 MB
g++	random_2_02	AC	27 ms	5 MB
g++	random_2_03	AC	36 ms	5 MB
g++	random_2_04	AC	19 ms	4 MB
g++	small_random_1_00	AC	7 ms	4 MB
g++	small_random_1_01	AC	7 ms	4 MB
g++	small_random_1_02	AC	7 ms	4 MB
g++	small_random_2_00	AC	7 ms	4 MB
g++	small_random_2_01	AC	7 ms	4 MB
g++	small_random_2_02	AC	7 ms	4 MB
clang++	example_00	AC	6 ms	4 MB
clang++	example_01	AC	6 ms	4 MB
clang++	example_02	AC	6 ms	4 MB
clang++	large_cycle_00	AC	47 ms	10 MB
clang++	max_random_00	AC	75 ms	15 MB
clang++	max_random_01	AC	76 ms	15 MB
clang++	max_random_02	AC	74 ms	15 MB
clang++	random_1_00	AC	55 ms	10 MB
clang++	random_1_01	AC	59 ms	12 MB
clang++	random_1_02	AC	37 ms	6 MB
clang++	random_2_00	AC	24 ms	4 MB
clang++	random_2_01	AC	10 ms	4 MB
clang++	random_2_02	AC	30 ms	5 MB
clang++	random_2_03	AC	40 ms	5 MB
clang++	random_2_04	AC	21 ms	4 MB
clang++	small_random_1_00	AC	7 ms	4 MB
clang++	small_random_1_01	AC	7 ms	4 MB
clang++	small_random_1_02	AC	6 ms	4 MB
clang++	small_random_2_00	AC	6 ms	4 MB
clang++	small_random_2_01	AC	6 ms	4 MB
clang++	small_random_2_02	AC	6 ms	4 MB

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