#ifdef NACHIA #define _GLIBCXX_DEBUG #else // disable assert #define NDEBUG #endif #include #include #include #include using namespace std; using ll = long long; const ll INF = 1ll << 60; #define REP(i,n) for(ll i=0; i using V = vector; template void chmax(A& l, const B& r){ if(l < r) l = r; } template void chmin(A& l, const B& r){ if(r < l) l = r; } #include #include namespace nachia{ template class CsrArray{ public: struct ListRange{ using iterator = typename std::vector::iterator; iterator begi, endi; iterator begin() const { return begi; } iterator end() const { return endi; } int size() const { return (int)std::distance(begi, endi); } Elem& operator[](int i) const { return begi[i]; } }; struct ConstListRange{ using iterator = typename std::vector::const_iterator; iterator begi, endi; iterator begin() const { return begi; } iterator end() const { return endi; } int size() const { return (int)std::distance(begi, endi); } const Elem& operator[](int i) const { return begi[i]; } }; private: int m_n; std::vector m_list; std::vector m_pos; public: CsrArray() : m_n(0), m_list(), m_pos() {} static CsrArray Construct(int n, std::vector> items){ CsrArray res; res.m_n = n; std::vector buf(n+1, 0); for(auto& [u,v] : items){ ++buf[u]; } for(int i=1; i<=n; i++) buf[i] += buf[i-1]; res.m_list.resize(buf[n]); for(int i=(int)items.size()-1; i>=0; i--){ res.m_list[--buf[items[i].first]] = std::move(items[i].second); } res.m_pos = std::move(buf); return res; } static CsrArray FromRaw(std::vector list, std::vector pos){ CsrArray res; res.m_n = pos.size() - 1; res.m_list = std::move(list); res.m_pos = std::move(pos); return res; } ListRange operator[](int u) { return ListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; } ConstListRange operator[](int u) const { return ConstListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; } int size() const { return m_n; } int fullSize() const { return (int)m_list.size(); } }; } // namespace nachia namespace nachia{ struct Graph { public: struct Edge{ int from, to; void reverse(){ std::swap(from, to); } int xorval() const { return from ^ to; } }; Graph() : m_n(0), m_e(0), m_isUndir(false) {} explicit Graph(int n, bool undirected = false, int m = 0) : m_n(n), m_e(m), m_isUndir(undirected) {} explicit Graph(int n, const std::vector>& edges, int undirected = false) : m_n(n), m_isUndir(undirected){ m_e.resize(edges.size()); for(std::size_t i=0; i static Graph Input(Cin& cin, int n, bool undirected, int m, int offset = 0){ Graph res(n, undirected, m); for(int i=0; i> u >> v; res[i].from = u - offset; res[i].to = v - offset; } return res; } template static std::pair> InputWeighted(Cin& cin, int n, bool undirected, int m, int offset = 0){ Graph res(n, undirected, m); std::vector wt(m); for(int i=0; i> u >> v >> wt[i]; res[i].from = u - offset; res[i].to = v - offset; } return std::make_pair(std::move(res), std::move(wt)); } int numVertices() const noexcept { return m_n; } int numEdges() const noexcept { return int(m_e.size()); } int addNode() noexcept { return m_n++; } int addEdge(int from, int to){ m_e.push_back({ from, to }); return numEdges() - 1; } Edge& operator[](int ei) noexcept { return m_e[ei]; } const Edge& operator[](int ei) const noexcept { return m_e[ei]; } auto begin(){ return m_e.begin(); } auto end(){ return m_e.end(); } auto begin() const { return m_e.begin(); } auto end() const { return m_e.end(); } bool isUndirected() const noexcept { return m_isUndir; } void reverseEdges() noexcept { for(auto& e : m_e) e.reverse(); } void contract(int newV, const std::vector& mapping){ assert(numVertices() == int(mapping.size())); for(int i=0; i induce(int num, const std::vector& mapping) const { int n = numVertices(); assert(n == int(mapping.size())); for(int i=0; i indexV(n), newV(num); for(int i=0; i= 0) indexV[i] = newV[mapping[i]]++; std::vector res; res.reserve(num); for(int i=0; i= 0) res[mapping[e.to]].addEdge(indexV[e.from], indexV[e.to]); return res; } CsrArray getEdgeIndexArray(bool undirected) const { std::vector> src; src.reserve(numEdges() * (undirected ? 2 : 1)); for(int i=0; i::Construct(numVertices(), src); } CsrArray getEdgeIndexArray() const { return getEdgeIndexArray(isUndirected()); } CsrArray getAdjacencyArray(bool undirected) const { std::vector> src; src.reserve(numEdges() * (undirected ? 2 : 1)); for(auto e : m_e){ src.emplace_back(e.from, e.to); if(undirected) src.emplace_back(e.to, e.from); } return CsrArray::Construct(numVertices(), src); } CsrArray getAdjacencyArray() const { return getAdjacencyArray(isUndirected()); } private: int m_n; std::vector m_e; bool m_isUndir; }; } // namespace nachia void testcase(){ ll N, M; cin >> N >> M; auto graph = nachia::Graph::Input(cin, N, true, M, 1); auto adj = graph.getAdjacencyArray(); V used(N), deg(N); REP(i,N) deg[i] = adj[i].size(); V col(N, 5); V ord; REP(i,N) if(deg[i] <= 3){ ord.push_back(i); used[i] = 1; } REP(i,ord.size()){ ll v = ord[i]; for(ll w : adj[v]) if(!used[w] && --deg[w] == 3){ used[w] = 1; ord.push_back(w); } } reverse(ord.begin(), ord.end()); for(ll v : ord){ ll x = 0b11110; for(ll w : adj[v]) x -= x & 1 << col[w]; REP(j,5) if(x&(1<sync_with_stdio(0); testcase(); return 0; }