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#include "graph/ds/remove_one_edge_connectivity.hpp"
#include "graph/base.hpp" // 1 辺消したときに // u,v が連結か / 連結成分数 / v の連結成分サイズ struct Remove_One_Edge_Connectivity { int N, M; int n_comp_base; vc<pair<int, int>> edge; vc<int> root; vc<int> LID, RID; vc<bool> bridge; template <typename GT> Remove_One_Edge_Connectivity(GT& G) { build(G); } template <typename GT> void build(GT& G) { N = G.N, M = G.M; edge.resize(M); for (auto& e: G.edges) edge[e.id] = {e.frm, e.to}; root.assign(N, -1); LID.assign(N, -1), RID.assign(N, -1); bridge.assign(M, 0); vc<int> low(N, -1); n_comp_base = 0; int p = 0; auto dfs = [&](auto& dfs, int v, int last_e) -> void { low[v] = LID[v] = p++; for (auto&& e: G[v]) { if (e.id == last_e) continue; if (root[e.to] == -1) { root[e.to] = root[v]; dfs(dfs, e.to, e.id); chmin(low[v], low[e.to]); bridge[e.id] = (low[e.to] == LID[e.to]); } else { chmin(low[v], LID[e.to]); } } RID[v] = p; }; FOR(v, N) { if (root[v] == -1) { n_comp_base++, root[v] = v, dfs(dfs, v, -1); } } for (auto& [a, b]: edge) { if (in_subtree(a, b)) swap(a, b); } } int n_comp(int eid) { return n_comp_base + (bridge[eid] ? 1 : 0); } bool is_connected(int eid, int u, int v) { if (root[u] != root[v]) return false; if (!bridge[eid]) return true; auto [a, b] = edge[eid]; return (in_subtree(u, b) == in_subtree(v, b)); } int size(int eid, int v) { int r = root[v]; if (!bridge[eid]) { return subtree_size(r); } auto [a, b] = edge[eid]; if (root[a] != r) { return subtree_size(r); } if (in_subtree(v, b)) return subtree_size(b); return subtree_size(r) - subtree_size(b); } private: bool in_subtree(int a, int b) { return LID[b] <= LID[a] && LID[a] < RID[b]; } int subtree_size(int v) { return RID[v] - LID[v]; } };
#line 2 "graph/base.hpp" template <typename T> struct Edge { int frm, to; T cost; int id; }; template <typename T = int, bool directed = false> struct Graph { static constexpr bool is_directed = directed; int N, M; using cost_type = T; using edge_type = Edge<T>; vector<edge_type> edges; vector<int> indptr; vector<edge_type> csr_edges; vc<int> vc_deg, vc_indeg, vc_outdeg; bool prepared; class OutgoingEdges { public: OutgoingEdges(const Graph* G, int l, int r) : G(G), l(l), r(r) {} const edge_type* begin() const { if (l == r) { return 0; } return &G->csr_edges[l]; } const edge_type* end() const { if (l == r) { return 0; } return &G->csr_edges[r]; } private: const Graph* G; int l, r; }; bool is_prepared() { return prepared; } Graph() : N(0), M(0), prepared(0) {} Graph(int N) : N(N), M(0), prepared(0) {} void build(int n) { N = n, M = 0; prepared = 0; edges.clear(); indptr.clear(); csr_edges.clear(); vc_deg.clear(); vc_indeg.clear(); vc_outdeg.clear(); } void add(int frm, int to, T cost = 1, int i = -1) { assert(!prepared); assert(0 <= frm && 0 <= to && to < N); if (i == -1) i = M; auto e = edge_type({frm, to, cost, i}); edges.eb(e); ++M; } #ifdef FASTIO // wt, off void read_tree(bool wt = false, int off = 1) { read_graph(N - 1, wt, off); } void read_graph(int M, bool wt = false, int off = 1) { for (int m = 0; m < M; ++m) { INT(a, b); a -= off, b -= off; if (!wt) { add(a, b); } else { T c; read(c); add(a, b, c); } } build(); } #endif void build() { assert(!prepared); prepared = true; indptr.assign(N + 1, 0); for (auto&& e: edges) { indptr[e.frm + 1]++; if (!directed) indptr[e.to + 1]++; } for (int v = 0; v < N; ++v) { indptr[v + 1] += indptr[v]; } auto counter = indptr; csr_edges.resize(indptr.back() + 1); for (auto&& e: edges) { csr_edges[counter[e.frm]++] = e; if (!directed) csr_edges[counter[e.to]++] = edge_type({e.to, e.frm, e.cost, e.id}); } } OutgoingEdges operator[](int v) const { assert(prepared); return {this, indptr[v], indptr[v + 1]}; } vc<int> deg_array() { if (vc_deg.empty()) calc_deg(); return vc_deg; } pair<vc<int>, vc<int>> deg_array_inout() { if (vc_indeg.empty()) calc_deg_inout(); return {vc_indeg, vc_outdeg}; } int deg(int v) { if (vc_deg.empty()) calc_deg(); return vc_deg[v]; } int in_deg(int v) { if (vc_indeg.empty()) calc_deg_inout(); return vc_indeg[v]; } int out_deg(int v) { if (vc_outdeg.empty()) calc_deg_inout(); return vc_outdeg[v]; } #ifdef FASTIO void debug() { print("Graph"); if (!prepared) { print("frm to cost id"); for (auto&& e: edges) print(e.frm, e.to, e.cost, e.id); } else { print("indptr", indptr); print("frm to cost id"); FOR(v, N) for (auto&& e: (*this)[v]) print(e.frm, e.to, e.cost, e.id); } } #endif vc<int> new_idx; vc<bool> used_e; // G における頂点 V[i] が、新しいグラフで i になるようにする // {G, es} Graph<T, directed> rearrange(vc<int> V, bool keep_eid = 0) { if (len(new_idx) != N) new_idx.assign(N, -1); int n = len(V); FOR(i, n) new_idx[V[i]] = i; Graph<T, directed> G(n); vc<int> history; FOR(i, n) { for (auto&& e: (*this)[V[i]]) { if (len(used_e) <= e.id) used_e.resize(e.id + 1); if (used_e[e.id]) continue; int a = e.frm, b = e.to; if (new_idx[a] != -1 && new_idx[b] != -1) { history.eb(e.id); used_e[e.id] = 1; int eid = (keep_eid ? e.id : -1); G.add(new_idx[a], new_idx[b], e.cost, eid); } } } FOR(i, n) new_idx[V[i]] = -1; for (auto&& eid: history) used_e[eid] = 0; G.build(); return G; } private: void calc_deg() { assert(vc_deg.empty()); vc_deg.resize(N); for (auto&& e: edges) vc_deg[e.frm]++, vc_deg[e.to]++; } void calc_deg_inout() { assert(vc_indeg.empty()); vc_indeg.resize(N); vc_outdeg.resize(N); for (auto&& e: edges) { vc_indeg[e.to]++, vc_outdeg[e.frm]++; } } }; #line 2 "graph/ds/remove_one_edge_connectivity.hpp" // 1 辺消したときに // u,v が連結か / 連結成分数 / v の連結成分サイズ struct Remove_One_Edge_Connectivity { int N, M; int n_comp_base; vc<pair<int, int>> edge; vc<int> root; vc<int> LID, RID; vc<bool> bridge; template <typename GT> Remove_One_Edge_Connectivity(GT& G) { build(G); } template <typename GT> void build(GT& G) { N = G.N, M = G.M; edge.resize(M); for (auto& e: G.edges) edge[e.id] = {e.frm, e.to}; root.assign(N, -1); LID.assign(N, -1), RID.assign(N, -1); bridge.assign(M, 0); vc<int> low(N, -1); n_comp_base = 0; int p = 0; auto dfs = [&](auto& dfs, int v, int last_e) -> void { low[v] = LID[v] = p++; for (auto&& e: G[v]) { if (e.id == last_e) continue; if (root[e.to] == -1) { root[e.to] = root[v]; dfs(dfs, e.to, e.id); chmin(low[v], low[e.to]); bridge[e.id] = (low[e.to] == LID[e.to]); } else { chmin(low[v], LID[e.to]); } } RID[v] = p; }; FOR(v, N) { if (root[v] == -1) { n_comp_base++, root[v] = v, dfs(dfs, v, -1); } } for (auto& [a, b]: edge) { if (in_subtree(a, b)) swap(a, b); } } int n_comp(int eid) { return n_comp_base + (bridge[eid] ? 1 : 0); } bool is_connected(int eid, int u, int v) { if (root[u] != root[v]) return false; if (!bridge[eid]) return true; auto [a, b] = edge[eid]; return (in_subtree(u, b) == in_subtree(v, b)); } int size(int eid, int v) { int r = root[v]; if (!bridge[eid]) { return subtree_size(r); } auto [a, b] = edge[eid]; if (root[a] != r) { return subtree_size(r); } if (in_subtree(v, b)) return subtree_size(b); return subtree_size(r) - subtree_size(b); } private: bool in_subtree(int a, int b) { return LID[b] <= LID[a] && LID[a] < RID[b]; } int subtree_size(int v) { return RID[v] - LID[v]; } };