#include <algorithm> #include <iostream> #include <iterator> #include <queue> #include <vector> //#define DEBUG #ifdef DEBUG constexpr const bool debug = true; #else constexpr const bool debug = false; #endif class graph_t { private: std::vector<std::vector<size_t>> adj; public: using vertex_t = size_t; void resize(size_t sz) { adj.clear(); adj.resize(sz); } void add_edge(vertex_t a, vertex_t b) { adj[a].push_back(b); adj[b].push_back(a); } const std::vector<size_t>& operator[](size_t idx) const { return adj[idx]; } auto begin() const -> decltype(adj.cbegin()) { return adj.cbegin(); } auto end() const -> decltype(adj.cend()) { return adj.cend(); } }; struct input_t { graph_t graph; size_t n, m, d; friend std::istream& operator>>(std::istream &str, input_t &input) { str >> input.n >> input.m >> input.d; input.graph.resize(input.n); for(size_t i = 0; i < input.m; ++i) { graph_t::vertex_t u, v; str >> u >> v; input.graph.add_edge(u - 1, v - 1); } return str; } }; class output_t { public: using vertex_t = graph_t::vertex_t; template<class... Args> output_t(Args&&... args) : data(std::forward<Args>(args)...) { std::sort(data.begin(), data.end()); } friend std::ostream& operator<<(std::ostream &str, const output_t &output) { if(output.data.empty()) str << "NIE" << std::endl; else { str << output.data.size() << std::endl; for(const auto v: output.data) str << v + 1 << " "; str << std::endl; } return str; } private: std::vector<vertex_t> data; }; class solver_t { public: using vertex_t = graph_t::vertex_t; using component_t = size_t; solver_t() = default; solver_t(const solver_t &) = delete; solver_t(solver_t &&) = default; template<class Input> explicit solver_t(Input &&input) : input(std::forward<Input>(input)) , data(input.n) { } output_t operator()() && { fill_degrees(); prepare_queue(); eliminate(); auto c = get_component(); return retrieve_component(c); } private: struct vertex_data { static constexpr const component_t NOT_VISITED = -1; bool removed; size_t degree; component_t component; vertex_data() : removed{false} , degree{0} , component{NOT_VISITED} { } }; void fill_degrees() { for(size_t i = 0; i < input.n; ++i) for(vertex_t j: input.graph[i]) data[j].degree++; } void prepare_queue() { for(size_t i = 0; i < input.n; ++i) if(data[i].degree < input.d) { queue.emplace(i); data[i].removed = true; } } void eliminate() { while(!queue.empty()) { const auto u = queue.front(); queue.pop(); if(debug) std::cerr << "removing " << u << std::endl; for(const auto v: input.graph[u]) { if(!data[v].removed && --data[v].degree < input.d) { data[v].removed = true; queue.emplace(v); } } } } size_t dfs(const vertex_t v, const component_t c) { if(data[v].component != vertex_data::NOT_VISITED) return 0; if(debug) std::cerr << "dfs(" << v << ", " << c << ")" << std::endl; data[v].component = c; size_t res = 1; for(const auto u: input.graph[v]) if(!data[u].removed) res += dfs(u, c); return res; } component_t get_component() { size_t best_size = 0; component_t best = vertex_data::NOT_VISITED; for(size_t i = 0; i < input.n; ++i) if(!data[i].removed && data[i].component == vertex_data::NOT_VISITED) { size_t current = dfs(i, i); if(debug) std::cerr << "Component with " << i << ": " << current << std::endl; if(current > best_size) { best_size = current; best = i; } } return best; } std::vector<vertex_t> retrieve_component(const component_t c) const { if(c == vertex_data::NOT_VISITED) return {}; std::vector<vertex_t> res; for(size_t i = 0; i < input.n; ++i) if(data[i].component == c) res.push_back(i); return res; } const input_t input; std::vector<vertex_data> data; std::queue<vertex_t> queue; }; int main() { std::ios_base::sync_with_stdio(false); input_t input; std::cin >> input; std::cout << solver_t{std::move(input)}(); }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 | #include <algorithm> #include <iostream> #include <iterator> #include <queue> #include <vector> //#define DEBUG #ifdef DEBUG constexpr const bool debug = true; #else constexpr const bool debug = false; #endif class graph_t { private: std::vector<std::vector<size_t>> adj; public: using vertex_t = size_t; void resize(size_t sz) { adj.clear(); adj.resize(sz); } void add_edge(vertex_t a, vertex_t b) { adj[a].push_back(b); adj[b].push_back(a); } const std::vector<size_t>& operator[](size_t idx) const { return adj[idx]; } auto begin() const -> decltype(adj.cbegin()) { return adj.cbegin(); } auto end() const -> decltype(adj.cend()) { return adj.cend(); } }; struct input_t { graph_t graph; size_t n, m, d; friend std::istream& operator>>(std::istream &str, input_t &input) { str >> input.n >> input.m >> input.d; input.graph.resize(input.n); for(size_t i = 0; i < input.m; ++i) { graph_t::vertex_t u, v; str >> u >> v; input.graph.add_edge(u - 1, v - 1); } return str; } }; class output_t { public: using vertex_t = graph_t::vertex_t; template<class... Args> output_t(Args&&... args) : data(std::forward<Args>(args)...) { std::sort(data.begin(), data.end()); } friend std::ostream& operator<<(std::ostream &str, const output_t &output) { if(output.data.empty()) str << "NIE" << std::endl; else { str << output.data.size() << std::endl; for(const auto v: output.data) str << v + 1 << " "; str << std::endl; } return str; } private: std::vector<vertex_t> data; }; class solver_t { public: using vertex_t = graph_t::vertex_t; using component_t = size_t; solver_t() = default; solver_t(const solver_t &) = delete; solver_t(solver_t &&) = default; template<class Input> explicit solver_t(Input &&input) : input(std::forward<Input>(input)) , data(input.n) { } output_t operator()() && { fill_degrees(); prepare_queue(); eliminate(); auto c = get_component(); return retrieve_component(c); } private: struct vertex_data { static constexpr const component_t NOT_VISITED = -1; bool removed; size_t degree; component_t component; vertex_data() : removed{false} , degree{0} , component{NOT_VISITED} { } }; void fill_degrees() { for(size_t i = 0; i < input.n; ++i) for(vertex_t j: input.graph[i]) data[j].degree++; } void prepare_queue() { for(size_t i = 0; i < input.n; ++i) if(data[i].degree < input.d) { queue.emplace(i); data[i].removed = true; } } void eliminate() { while(!queue.empty()) { const auto u = queue.front(); queue.pop(); if(debug) std::cerr << "removing " << u << std::endl; for(const auto v: input.graph[u]) { if(!data[v].removed && --data[v].degree < input.d) { data[v].removed = true; queue.emplace(v); } } } } size_t dfs(const vertex_t v, const component_t c) { if(data[v].component != vertex_data::NOT_VISITED) return 0; if(debug) std::cerr << "dfs(" << v << ", " << c << ")" << std::endl; data[v].component = c; size_t res = 1; for(const auto u: input.graph[v]) if(!data[u].removed) res += dfs(u, c); return res; } component_t get_component() { size_t best_size = 0; component_t best = vertex_data::NOT_VISITED; for(size_t i = 0; i < input.n; ++i) if(!data[i].removed && data[i].component == vertex_data::NOT_VISITED) { size_t current = dfs(i, i); if(debug) std::cerr << "Component with " << i << ": " << current << std::endl; if(current > best_size) { best_size = current; best = i; } } return best; } std::vector<vertex_t> retrieve_component(const component_t c) const { if(c == vertex_data::NOT_VISITED) return {}; std::vector<vertex_t> res; for(size_t i = 0; i < input.n; ++i) if(data[i].component == c) res.push_back(i); return res; } const input_t input; std::vector<vertex_data> data; std::queue<vertex_t> queue; }; int main() { std::ios_base::sync_with_stdio(false); input_t input; std::cin >> input; std::cout << solver_t{std::move(input)}(); } |