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/general_matching" #include "../../template/template.hpp" #include "../../graph/flow/gabow-edmonds.hpp" int main() { int N, M; cin >> N >> M; GabowEdmonds flow(N); for(int i = 0; i < M; i++) { int a, b; cin >> a >> b; flow.add_edge(a, b); } auto ret = flow.max_matching(); cout << ret.size() << endl; for(auto &p : ret) cout << p << endl; }
#line 1 "test/verify/yosupo-general-matching.test.cpp" #define PROBLEM "https://judge.yosupo.jp/problem/general_matching" #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-general-matching.test.cpp" #line 1 "graph/flow/gabow-edmonds.hpp" // https://qiita.com/Kutimoti_T/items/5b579773e0a24d650bdf /** * @brief Gabow Edmonds(一般グラフの最大マッチング) * @docs docs/gabow-edmonds.md */ struct GabowEdmonds { struct edge { int to, idx; }; vector< vector< edge > > g; vector< pair< int, int > > edges; vector< int > mate, label, first; queue< int > que; GabowEdmonds(int n) : g(n + 1), mate(n + 1), label(n + 1, -1), first(n + 1) {} void add_edge(int u, int v) { ++u, ++v; g[u].push_back((edge) {v, (int) (edges.size() + g.size())}); g[v].push_back((edge) {u, (int) (edges.size() + g.size())}); edges.emplace_back(u, v); } int find(int x) { if(label[first[x]] < 0) return first[x]; first[x] = find(first[x]); return first[x]; } void rematch(int v, int w) { int t = mate[v]; mate[v] = w; if(mate[t] != v) return; if(label[v] < (int)g.size()) { mate[t] = label[v]; rematch(label[v], t); } else { int x = edges[label[v] - g.size()].first; int y = edges[label[v] - g.size()].second; rematch(x, y); rematch(y, x); } } void assign_label(int x, int y, int num) { int r = find(x); int s = find(y); int join = 0; if(r == s) return; label[r] = -num; label[s] = -num; while(true) { if(s != 0) swap(r, s); r = find(label[mate[r]]); if(label[r] == -num) { join = r; break; } label[r] = -num; } int v = first[x]; while(v != join) { que.push(v); label[v] = num; first[v] = join; v = first[label[mate[v]]]; } v = first[y]; while(v != join) { que.push(v); label[v] = num; first[v] = join; v = first[label[mate[v]]]; } } bool augment_check(int u) { que = queue< int >(); first[u] = 0; label[u] = 0; que.push(u); while(!que.empty()) { int x = que.front(); que.pop(); for(auto e : g[x]) { int y = e.to; if(mate[y] == 0 && y != u) { mate[y] = x; rematch(x, y); return true; } else if(label[y] >= 0) { assign_label(x, y, e.idx); } else if(label[mate[y]] < 0) { label[mate[y]] = x; first[mate[y]] = y; que.push(mate[y]); } } } return false; } vector< pair< int, int > > max_matching() { for(int i = 1; i < (int)g.size(); i++) { if(mate[i] != 0) continue; if(augment_check(i)) label.assign(g.size(), -1); } vector< pair< int, int > > ret; for(int i = 1; i < (int)g.size(); i++) { if(i < mate[i]) ret.emplace_back(i - 1, mate[i] - 1); } return ret; } }; #line 6 "test/verify/yosupo-general-matching.test.cpp" int main() { int N, M; cin >> N >> M; GabowEdmonds flow(N); for(int i = 0; i < M; i++) { int a, b; cin >> a >> b; flow.add_edge(a, b); } auto ret = flow.max_matching(); cout << ret.size() << endl; for(auto &p : ret) cout << p << endl; }