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#pragma once #include "template.cpp" #include "graph/graph.cpp" class TwoEdgeConnectedComponents { private: VI ord, low, par, index, sz; public: VVI components; Graph c_graph; public: TwoEdgeConnectedComponents() {} TwoEdgeConnectedComponents(const Graph& graph) : ord(graph.size(), -1), low(graph.size()), par(graph.size(), -1), index(graph.size(), -1), sz(graph.size(), 1) { int n = graph.size(); rep(i, n) if (ord[i] == -1) dfs(i, graph); rep(i, n) if (index[i] == -1) add_component(i, graph); c_graph = Graph(components.size()); rep(v, n) for (int u : graph[v]) if (index[v] != index[u]) c_graph[index[v]].emplace_back(index[u]); } private: int t = 0; void dfs(int v, const Graph& graph) { ord[v] = low[v] = t++; int dup = 0; for (int u : graph[v]) { if (u == par[v] and !dup) dup = 1; else if (ord[u] != -1) chmin(low[v], ord[u]); else { par[u] = v; dfs(u, graph); sz[v] += sz[u]; chmin(low[v], low[u]); } } } void fill_component(int v, const Graph& graph) { components[index[v]].emplace_back(v); for (int u : graph[v]) if (index[u] == -1 and not is_bridge(u, v)) { index[u] = index[v]; fill_component(u, graph); } } void add_component(int v, const Graph& graph) { index[v] = components.size(); components.emplace_back(); fill_component(v, graph); } public: bool is_bridge(int u, int v) const { if (ord[u] > ord[v]) swap(u, v); return ord[u] < low[v]; } int operator[](int v) const { return index[v]; } };
#line 2 "graph/two-edge-connected-components.cpp" #line 2 "template.cpp" #ifndef LOCAL #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #pragma GCC target("avx") #endif #include <algorithm> #include <bitset> #include <cassert> #include <cmath> #include <functional> #include <iostream> #include <map> #include <numeric> #include <queue> #include <set> #include <stack> using namespace std; using ll = long long; using ull = unsigned long long; using VI = vector<int>; using VVI = vector<vector<int>>; using VLL = vector<ll>; using VVLL = vector<vector<ll>>; using VB = vector<bool>; using PII = pair<int, int>; using PLL = pair<ll, ll>; constexpr int INF = 1000000007; constexpr ll INF_LL = 1'000'000'000'000'000'007; #define all(x) begin(x), end(x) #define rall(x) rbegin(x), rend(x) #define newl '\n' // loops rep(until) / rep(var, until) / rep(var, from, until) / repr (reversed order) #define OVERLOAD3(_1, _2, _3, name, ...) name #define rep(...) OVERLOAD3(__VA_ARGS__, REPEAT_FROM_UNTIL, REPEAT_UNTIL, REPEAT)(__VA_ARGS__) #define REPEAT(times) REPEAT_CNT(_repeat, __COUNTER__, times) #define REPEAT_CNT(_repeat, cnt, times) REPEAT_CNT_CAT(_repeat, cnt, times) #define REPEAT_CNT_CAT(_repeat, cnt, times) REPEAT_FROM_UNTIL(_repeat ## cnt, 0, times) #define REPEAT_UNTIL(name, times) REPEAT_FROM_UNTIL(name, 0, times) #define REPEAT_FROM_UNTIL(name, from, until) for (int name = from, name ## __until = (until); name < name ## __until; name++) #define repr(...) OVERLOAD3(__VA_ARGS__, REPR_FROM_UNTIL, REPR_UNTIL, REPEAT)(__VA_ARGS__) #define REPR_UNTIL(name, times) REPR_FROM_UNTIL(name, 0, times) #define REPR_FROM_UNTIL(name, from, until) for (int name = (until)-1, name ## __from = (from); name >= name ## __from; name--) template <typename T, typename U> bool chmin(T& var, U x) { if (var > x) { var = x; return true; } else return false; } template <typename T, typename U> bool chmax(T& var, U x) { if (var < x) { var = x; return true; } else return false; } ll power(ll e, ll t, ll mod = INF_LL) { ll res = 1; for (; t; t >>= 1, (e *= e) %= mod) if (t & 1) (res *= e) %= mod; return res; } ll choose(ll n, int r) { chmin(r, n-r); if (r < 0) return 0; ll res = 1; rep(i, r) res *= n-i, res /= i+1; return res; } template <typename T, typename U> T divceil(T m, U d) { return (m + d - 1) / d; } template <typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); } template <typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); } // debugging stuff #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wmisleading-indentation" #define repi(it, ds) for (auto it = ds.begin(); it != ds.end(); it++) class DebugPrint { public: template <typename T> DebugPrint& operator <<(const T& v) { #ifdef LOCAL cerr << v; #endif return *this; } } debugos; template <typename T> DebugPrint& operator<<(DebugPrint& os, const vector<T>& vec) { os << "{"; for (int i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : ", "); os << "}"; return os; } template <typename T, typename U> DebugPrint& operator<<(DebugPrint& os, const map<T, U>& map_var) { os << "{"; repi(itr, map_var) { os << * itr; itr++; if (itr != map_var.end()) os << ", "; itr--; } os << "}"; return os; } template < typename T> DebugPrint& operator<<(DebugPrint& os, const set<T>& set_var) { os << "{"; repi( itr, set_var) { os << *itr; itr++; if (itr != set_var.end()) os << ", "; itr--; } os << "}"; return os; } template <typename T, typename U> DebugPrint& operator<<(DebugPrint& os, const pair<T, U>& p) { os << "(" << p.first << ", " << p.second << ")"; return os; } void dump_func( ) { debugos << newl; } template <class Head, class... Tail> void dump_func(Head &&head, Tail &&... tail) { debugos << head; if (sizeof...(Tail) > 0) { debugos << ", "; } dump_func(forward <Tail>(tail)...); } #ifdef LOCAL #define dump(...) debugos << " " << string(#__VA_ARGS__) << ": " << "[" << to_string(__LINE__) \ << ":" << __FUNCTION__ << "]" << newl << " ", dump_func(__VA_ARGS__) #else #define dump(...) ({}) #endif #pragma GCC diagnostic pop #line 2 "graph/graph.cpp" #line 4 "graph/graph.cpp" struct Edge { int to; ll cost; Edge(int _to) : to(_to), cost(1) {} Edge(int _to, ll _cost) : to(_to), cost(_cost) {} operator int() const { return to; } }; using Graph = vector<vector<Edge>>; #line 5 "graph/two-edge-connected-components.cpp" class TwoEdgeConnectedComponents { private: VI ord, low, par, index, sz; public: VVI components; Graph c_graph; public: TwoEdgeConnectedComponents() {} TwoEdgeConnectedComponents(const Graph& graph) : ord(graph.size(), -1), low(graph.size()), par(graph.size(), -1), index(graph.size(), -1), sz(graph.size(), 1) { int n = graph.size(); rep(i, n) if (ord[i] == -1) dfs(i, graph); rep(i, n) if (index[i] == -1) add_component(i, graph); c_graph = Graph(components.size()); rep(v, n) for (int u : graph[v]) if (index[v] != index[u]) c_graph[index[v]].emplace_back(index[u]); } private: int t = 0; void dfs(int v, const Graph& graph) { ord[v] = low[v] = t++; int dup = 0; for (int u : graph[v]) { if (u == par[v] and !dup) dup = 1; else if (ord[u] != -1) chmin(low[v], ord[u]); else { par[u] = v; dfs(u, graph); sz[v] += sz[u]; chmin(low[v], low[u]); } } } void fill_component(int v, const Graph& graph) { components[index[v]].emplace_back(v); for (int u : graph[v]) if (index[u] == -1 and not is_bridge(u, v)) { index[u] = index[v]; fill_component(u, graph); } } void add_component(int v, const Graph& graph) { index[v] = components.size(); components.emplace_back(); fill_component(v, graph); } public: bool is_bridge(int u, int v) const { if (ord[u] > ord[v]) swap(u, v); return ord[u] < low[v]; } int operator[](int v) const { return index[v]; } };