This documentation is automatically generated by online-judge-tools/verification-helper
View the Project on GitHub ei1333/library
#define 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" #define 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 int mod = 1e9 + 7; 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"; } }