Tifa's CP Library

:warning: e_bcc (src/code/graph/e_bcc.hpp)

Depends on

Code

#ifndef TIFALIBS_GRAPH_E_BCC
#define TIFALIBS_GRAPH_E_BCC

#include "../util/util.hpp"

namespace tifa_libs::graph {

template <class EW>
class e_bcc {
  const vvec<EW> &g;

 public:
  u32 id;
  vecu ebcc_id, dfn, low;
  vecb cut;
  vvecu belongs;

  //! EW need rev_edge
  explicit e_bcc(vvec<EW> const &G) : g(G) { build(); }

  void build() {
    id = 0;
    u32 cnt = 0, n = u32(g.size());
    dfn = low = ebcc_id = vecu(n, n);
    cut = vecb(n, 0);
    std::stack<u32> s;

    auto dfs = [&](auto &&dfs, u32 u, u32 fa, u32 inv_from) -> void {
      dfn[u] = low[u] = cnt++;
      s.push(u);
      for (u32 i = 0; i < g[u].size(); ++i) {
        auto v = g[u][i];
        if (v.to == fa && i == inv_from) continue;
        if (dfn[v.to] == n) {
          dfs(dfs, v.to, u, v.inv);
          low[u] = std::min(low[u], low[v.to]);
        } else low[u] = std::min(low[u], dfn[v.to]);
      }
      if (low[u] == dfn[u]) {
        belongs.push_back(vecu());
        do {
          u32 v = s.top();
          s.pop();
          ebcc_id[v] = id;
          belongs[id].push_back(v);
          if (v == u) return void(++id);
        } while (1);
      }
    };

    for (u32 i = 0; i < n; ++i)
      if (dfn[i] == n) dfs(dfs, i, i, -1_u32);
  }
};

}  // namespace tifa_libs::graph

#endif
#line 1 "src/code/graph/e_bcc.hpp"



#line 1 "src/code/util/util.hpp"



#include <bits/stdc++.h>

template <class T>
constexpr T abs(T x) { return x < 0 ? -x : x; }

using i8 = int8_t;
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using isz = ptrdiff_t;

using u8 = uint8_t;
using u16 = uint16_t;
using u32 = uint32_t;
using u64 = uint64_t;
using u128 = __uint128_t;
using usz = size_t;

using f32 = float;
using f64 = double;
using f128 = long double;

template <class T>
using ptt = std::pair<T, T>;
template <class T>
using pt3 = std::tuple<T, T, T>;
template <class T>
using pt4 = std::tuple<T, T, T, T>;

template <class T, usz N>
using arr = std::array<T, N>;
template <class T>
using vec = std::vector<T>;
template <class T>
using vvec = vec<vec<T>>;
template <class T>
using v3ec = vec<vvec<T>>;
template <class U, class T>
using vecp = vec<std::pair<U, T>>;
template <class U, class T>
using vvecp = vvec<std::pair<U, T>>;
template <class T>
using vecpt = vec<ptt<T>>;
template <class T>
using vvecpt = vvec<ptt<T>>;

template <class T, class C = std::less<T>>
using pq = std::priority_queue<T, vec<T>, C>;
template <class T>
using pqg = std::priority_queue<T, vec<T>, std::greater<T>>;

using strn = std::string;
using strnv = std::string_view;

using vecu = vec<u32>;
using vvecu = vvec<u32>;
using v3ecu = v3ec<u32>;
using vecu64 = vec<u64>;
using vecb = vec<bool>;
using vvecb = vvec<bool>;

#ifdef ONLINE_JUDGE
#undef assert
#define assert(x) 42
#endif

using namespace std::literals;

constexpr i8 operator""_i8(unsigned long long x) { return (i8)x; }
constexpr i16 operator""_i16(unsigned long long x) { return (i16)x; }
constexpr i32 operator""_i32(unsigned long long x) { return (i32)x; }
constexpr i64 operator""_i64(unsigned long long x) { return (i64)x; }
constexpr isz operator""_iz(unsigned long long x) { return (isz)x; }

constexpr u8 operator""_u8(unsigned long long x) { return (u8)x; }
constexpr u16 operator""_u16(unsigned long long x) { return (u16)x; }
constexpr u32 operator""_u32(unsigned long long x) { return (u32)x; }
constexpr u64 operator""_u64(unsigned long long x) { return (u64)x; }
constexpr usz operator""_uz(unsigned long long x) { return (usz)x; }

inline const auto fn_0 = [](auto&&...) {};


#line 5 "src/code/graph/e_bcc.hpp"

namespace tifa_libs::graph {

template <class EW>
class e_bcc {
  const vvec<EW> &g;

 public:
  u32 id;
  vecu ebcc_id, dfn, low;
  vecb cut;
  vvecu belongs;

  //! EW need rev_edge
  explicit e_bcc(vvec<EW> const &G) : g(G) { build(); }

  void build() {
    id = 0;
    u32 cnt = 0, n = u32(g.size());
    dfn = low = ebcc_id = vecu(n, n);
    cut = vecb(n, 0);
    std::stack<u32> s;

    auto dfs = [&](auto &&dfs, u32 u, u32 fa, u32 inv_from) -> void {
      dfn[u] = low[u] = cnt++;
      s.push(u);
      for (u32 i = 0; i < g[u].size(); ++i) {
        auto v = g[u][i];
        if (v.to == fa && i == inv_from) continue;
        if (dfn[v.to] == n) {
          dfs(dfs, v.to, u, v.inv);
          low[u] = std::min(low[u], low[v.to]);
        } else low[u] = std::min(low[u], dfn[v.to]);
      }
      if (low[u] == dfn[u]) {
        belongs.push_back(vecu());
        do {
          u32 v = s.top();
          s.pop();
          ebcc_id[v] = id;
          belongs[id].push_back(v);
          if (v == u) return void(++id);
        } while (1);
      }
    };

    for (u32 i = 0; i < n; ++i)
      if (dfn[i] == n) dfs(dfs, i, i, -1_u32);
  }
};

}  // namespace tifa_libs::graph


Back to top page