#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using lint = long long; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector& vec, const V& val, int len) { vec.assign(len, val); } template void ndarray(vector& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); } template bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; } template bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; } int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template vector sort_unique(vector vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; } template int arglb(const std::vector &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); } template int argub(const std::vector &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); } template istream &operator>>(istream &is, vector &vec) { for (auto &v : vec) is >> v; return is; } template ostream &operator<<(ostream &os, const vector &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; } template ostream &operator<<(ostream &os, const array &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; } #if __cplusplus >= 201703L template istream &operator>>(istream &is, tuple &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; } template ostream &operator<<(ostream &os, const tuple &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; } #endif template ostream &operator<<(ostream &os, const deque &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; } template ostream &operator<<(ostream &os, const set &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const multiset &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const pair &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; } template ostream &operator<<(ostream &os, const map &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } #ifdef HITONANODE_LOCAL const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m"; #define dbg(x) cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl #define dbgif(cond, x) ((cond) ? cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl : cerr) #else #define dbg(x) (x) #define dbgif(cond, x) 0 #endif // Bipartite matching of undirected bipartite graph (Hopcroft-Karp) // https://ei1333.github.io/luzhiled/snippets/graph/hopcroft-karp.html // Comprexity: O((V + E)sqrtV) // int solve(): enumerate maximum number of matching / return -1 (if graph is not bipartite) struct BipartiteMatching { int V; std::vector> to; // Adjacency list std::vector dist; // dist[i] = (Distance from i'th node) std::vector match; // match[i] = (Partner of i'th node) or -1 (No parter) std::vector used, vv; std::vector color; // color of each node(checking bipartition): 0/1/-1(not determined) BipartiteMatching() = default; BipartiteMatching(int V_) : V(V_), to(V_), match(V_, -1), used(V_), color(V_, -1) {} void add_edge(int u, int v) { assert(u >= 0 and u < V and v >= 0 and v < V and u != v); to[u].push_back(v); to[v].push_back(u); } void _bfs() { dist.assign(V, -1); std::vector q; int lq = 0; for (int i = 0; i < V; i++) { if (!color[i] and !used[i]) q.push_back(i), dist[i] = 0; } while (lq < int(q.size())) { int now = q[lq++]; for (auto nxt : to[now]) { int c = match[nxt]; if (c >= 0 and dist[c] == -1) q.push_back(c), dist[c] = dist[now] + 1; } } } bool _dfs(int now) { vv[now] = true; for (auto nxt : to[now]) { int c = match[nxt]; if (c < 0 or (!vv[c] and dist[c] == dist[now] + 1 and _dfs(c))) { match[nxt] = now, match[now] = nxt; used[now] = true; return true; } } return false; } bool _color_bfs(int root) { color[root] = 0; std::vector q{root}; int lq = 0; while (lq < int(q.size())) { int now = q[lq++], c = color[now]; for (auto nxt : to[now]) { if (color[nxt] == -1) { color[nxt] = !c, q.push_back(nxt); } else if (color[nxt] == c) { return false; } } } return true; } int solve() { for (int i = 0; i < V; i++) { if (color[i] == -1 and !_color_bfs(i)) return -1; } int ret = 0; while (true) { _bfs(); vv.assign(V, false); int flow = 0; for (int i = 0; i < V; i++) { if (!color[i] and !used[i] and _dfs(i)) flow++; } if (!flow) break; ret += flow; } return ret; } template friend OStream &operator<<(OStream &os, const BipartiteMatching &bm) { os << "{N=" << bm.V << ':'; for (int i = 0; i < bm.V; i++) { if (bm.match[i] > i) os << '(' << i << '-' << bm.match[i] << "),"; } return os << '}'; } }; // Directed graph library to find strongly connected components (強連結成分分解) // 0-indexed directed graph // Complexity: O(V + E) struct DirectedGraphSCC { int V; // # of Vertices std::vector> to, from; std::vector used; // Only true/false std::vector vs; std::vector cmp; int scc_num = -1; DirectedGraphSCC(int V = 0) : V(V), to(V), from(V), cmp(V) {} void _dfs(int v) { used[v] = true; for (auto t : to[v]) if (!used[t]) _dfs(t); vs.push_back(v); } void _rdfs(int v, int k) { used[v] = true; cmp[v] = k; for (auto t : from[v]) if (!used[t]) _rdfs(t, k); } void add_edge(int from_, int to_) { assert(from_ >= 0 and from_ < V and to_ >= 0 and to_ < V); to[from_].push_back(to_); from[to_].push_back(from_); } // Detect strongly connected components and return # of them. // Also, assign each vertex `v` the scc id `cmp[v]` (0-indexed) int FindStronglyConnectedComponents() { used.assign(V, false); vs.clear(); for (int v = 0; v < V; v++) if (!used[v]) _dfs(v); used.assign(V, false); scc_num = 0; for (int i = (int)vs.size() - 1; i >= 0; i--) if (!used[vs[i]]) _rdfs(vs[i], scc_num++); return scc_num; } // Find and output the vertices that form a closed cycle. // output: {v_1, ..., v_C}, where C is the length of cycle, // {} if there's NO cycle (graph is DAG) int _c, _init; std::vector _ret_cycle; bool _dfs_detectcycle(int now, bool b0) { if (now == _init and b0) return true; for (auto nxt : to[now]) if (cmp[nxt] == _c and !used[nxt]) { _ret_cycle.emplace_back(nxt), used[nxt] = 1; if (_dfs_detectcycle(nxt, true)) return true; _ret_cycle.pop_back(); } return false; } std::vector DetectCycle() { int ns = FindStronglyConnectedComponents(); if (ns == V) return {}; std::vector cnt(ns); for (auto x : cmp) cnt[x]++; _c = std::find_if(cnt.begin(), cnt.end(), [](int x) { return x > 1; }) - cnt.begin(); _init = std::find(cmp.begin(), cmp.end(), _c) - cmp.begin(); used.assign(V, false); _ret_cycle.clear(); _dfs_detectcycle(_init, false); return _ret_cycle; } // After calling `FindStronglyConnectedComponents()`, generate a new graph by uniting all vertices // belonging to the same component(The resultant graph is DAG). DirectedGraphSCC GenerateTopologicalGraph() { DirectedGraphSCC newgraph(scc_num); for (int s = 0; s < V; s++) for (auto t : to[s]) { if (cmp[s] != cmp[t]) newgraph.add_edge(cmp[s], cmp[t]); } return newgraph; } }; // 2-SAT solver: Find a solution for `(Ai v Aj) ^ (Ak v Al) ^ ... = true` // - `nb_sat_vars`: Number of variables // - Considering a graph with `2 * nb_sat_vars` vertices // - Vertices [0, nb_sat_vars) means `Ai` // - vertices [nb_sat_vars, 2 * nb_sat_vars) means `not Ai` struct SATSolver : DirectedGraphSCC { int nb_sat_vars; std::vector solution; SATSolver(int nb_variables = 0) : DirectedGraphSCC(nb_variables * 2), nb_sat_vars(nb_variables), solution(nb_sat_vars) {} void add_x_or_y_constraint(bool is_x_true, int x, bool is_y_true, int y) { assert(x >= 0 and x < nb_sat_vars); assert(y >= 0 and y < nb_sat_vars); if (!is_x_true) x += nb_sat_vars; if (!is_y_true) y += nb_sat_vars; add_edge((x + nb_sat_vars) % (nb_sat_vars * 2), y); add_edge((y + nb_sat_vars) % (nb_sat_vars * 2), x); } // Solve the 2-SAT problem. If no solution exists, return `false`. // Otherwise, dump one solution to `solution` and return `true`. bool run() { FindStronglyConnectedComponents(); for (int i = 0; i < nb_sat_vars; i++) { if (cmp[i] == cmp[i + nb_sat_vars]) return false; solution[i] = cmp[i] > cmp[i + nb_sat_vars]; } return true; } }; // Dulmage–Mendelsohn (DM) decomposition (DM 分解) // return: [(W+0, W-0), (W+1,W-1),...,(W+(k+1), W-(k+1))] // : sequence of pair (left vetrices, right vertices) // - |W+0| < |W-0| or both empty // - |W+i| = |W-i| (i = 1, ..., k) // - |W+(k+1)| > |W-(k+1)| or both empty // - W is topologically sorted // Example: // (2, 2, [(0,0), (0,1), (1,0)]) => [([],[]),([0,],[1,]),([1,],[0,]),([],[]),] // Complexity: O(N + (N + M) sqrt(N)) // Verified: https://yukicoder.me/problems/no/1615 std::vector, std::vector>> dulmage_mendelsohn(int L, int R, const std::vector> &edges) { for (auto p : edges) { assert(0 <= p.first and p.first < L); assert(0 <= p.second and p.second < R); } BipartiteMatching bm(L + R); for (auto p : edges) bm.add_edge(p.first, L + p.second); bm.solve(); DirectedGraphSCC scc(L + R); for (auto p : edges) scc.add_edge(p.first, L + p.second); for (int l = 0; l < L; ++l) { if (bm.match[l] >= L) scc.add_edge(bm.match[l], l); } int nscc = scc.FindStronglyConnectedComponents(); std::vector cmp_map(nscc, -2); std::vector vis(L + R); std::vector st; for (int c = 0; c < 2; ++c) { std::vector> to(L + R); auto color = [&L](int x) { return x >= L; }; for (auto p : edges) { int u = p.first, v = L + p.second; if (color(u) != c) std::swap(u, v); to[u].push_back(v); if (bm.match[u] == v) to[v].push_back(u); } for (int i = 0; i < L + R; ++i) { if (bm.match[i] >= 0 or color(i) != c or vis[i]) continue; vis[i] = 1, st = {i}; while (!st.empty()) { int now = st.back(); cmp_map[scc.cmp[now]] = c - 1; st.pop_back(); for (int nxt : to[now]) { if (!vis[nxt]) vis[nxt] = 1, st.push_back(nxt); } } } } int nset = 1; for (int n = 0; n < nscc; ++n) { if (cmp_map[n] == -2) cmp_map[n] = nset++; } for (auto &x : cmp_map) { if (x == -1) x = nset; } nset++; std::vector, std::vector>> groups(nset); for (int l = 0; l < L; ++l) { if (bm.match[l] < 0) continue; int c = cmp_map[scc.cmp[l]]; groups[c].first.push_back(l); groups[c].second.push_back(bm.match[l] - L); } for (int l = 0; l < L; ++l) { if (bm.match[l] >= 0) continue; int c = cmp_map[scc.cmp[l]]; groups[c].first.push_back(l); } for (int r = 0; r < R; ++r) { if (bm.match[L + r] >= 0) continue; int c = cmp_map[scc.cmp[L + r]]; groups[c].second.push_back(r); } return groups; } int main() { int N, M, L; cin >> N >> M >> L; vector edges(L); for (auto &[s, t] : edges) { cin >> s >> t; s--, t--; } dbg(edges); auto dm = dulmage_mendelsohn(N, M, edges); dbg(dm); vector grp1(N, -1), grp2(M, -1); REP(g, dm.size()) { for (auto i : dm[g].first) grp1[i] = g; for (auto i : dm[g].second) grp2[i] = g; } dbg(grp1); dbg(grp2); for (auto [s, t] : edges) { if (grp1[s] == grp2[t]) puts("Yes"); else puts("No"); } }