#pragma region template #include using namespace std; using ll = long long; using ull = unsigned long long; using ld = long double; using vi = vector; using vvi = vector; using vvvi = vector; using vll = vector; using vvll = vector; using vvvll = vector; using vld = vector; using vvld = vector; using vvvld = vector; using vs = vector; using pll = pair; using vp = vector; template using pqrev = priority_queue, greater>; #define rep(i, n) for (ll i = 0, i##_end = (n); i < i##_end; i++) #define repb(i, n) for (ll i = (n)-1; i >= 0; i--) #define repr(i, a, b) for (ll i = (a), i##_end = (b); i < i##_end; i++) #define reprb(i, a, b) for (ll i = (b)-1, i##_end = (a); i >= i##_end; i--) #define ALL(a) (a).begin(), (a).end() #define SZ(x) ((ll)(x).size()) //* constexpr ll MOD = 1e9 + 7; /*/ constexpr ll MOD = 998244353; //*/ constexpr ll INF = 1e+18; constexpr ld EPS = 1e-12L; constexpr ld PI = 3.14159265358979323846L; constexpr ll GCD(ll a, ll b) { return b ? GCD(b, a % b) : a; } constexpr ll LCM(ll a, ll b) { return a / GCD(a, b) * b; } template constexpr bool chmax(S &a, const T &b) { if (a < b) { a = b; return 1; } return 0; } template constexpr bool chmin(S &a, const T &b) { if (b < a) { a = b; return 1; } return 0; } #ifdef OJ_LOCAL #include "dump.hpp" #else #define dump(...) ((void)0) #endif template bool print_(const T &a) { cout << a; return true; } template bool print_(const vector &vec) { for (auto &a : vec) { cout << a; if (&a != &vec.back()) { cout << " "; } } return false; } template bool print_(const vector> &vv) { for (auto &v : vv) { for (auto &a : v) { cout << a; if (&a != &v.back()) { cout << " "; } } if (&v != &vv.back()) { cout << "\n"; } } return false; } void print() { cout << "\n"; } template void print(Head &&head, Tail &&... tail) { bool f = print_(head); if (sizeof...(tail) != 0) { cout << (f ? " " : "\n"); } print(forward(tail)...); } #pragma endregion template struct Edge { int from, to; T cost; int id; Edge(int from_, int to_, T cost_, int id_) : from(from_), to(to_), cost(cost_), id(id_) {} Edge(int from_, int to_, T cost_) : from(from_), to(to_), cost(cost_) {} Edge(int from_, int to_) : from(from_), to(to_), cost(1) {} bool operator<(const Edge &r) { return cost < r.cost; } }; template ostream &operator<<(ostream &os, Edge edge) { os << edge.from << " -> " << edge.to << " (" << edge.cost << ")"; return os; } // グラフテンプレート(隣接リスト) template > struct GraphL { // 頂点数、辺数 int n, m; // 隣接リスト vector> adj; GraphL(int n_) : n(n_), m(0), adj(n_) {} template void add_edge(int from, int to, Args... args) { adj[from].emplace_back(from, to, args...); m++; } vector &operator[](int i) { return adj[i]; } }; template > ostream &operator<<(ostream &os, GraphL graph) { os << "V = " << graph.n << ", E = " << graph.m << "\n"; for (const auto &ev : graph.adj) { for (const auto &e : ev) { os << e << "\n"; } } return os; } void Pr(bool f){ cout << (f ? "Yes" : "No") << "\n"; exit(0); } template vector TopologicalSort(GraphL &graph) { vector ret; vector visited(graph.n, false); auto dfs = [&](auto &Self, int node) -> void { if(!visited[node]){ visited[node] = true; for (auto &&e : graph.adj[node]) { Self(Self, e.to); } ret.emplace_back(node); } }; for (int i = 0; i < graph.n; i++) { dfs(dfs, i); } reverse(ret.begin(), ret.end()); vector chk(graph.n); for (int i = 0; i < graph.n; i++) { chk[ret[i]] = i; } for (int i = 0; i < graph.n; i++) { for(auto&& e: graph.adj[i]) { if(chk[i] >= chk[e.to]){ return vector(); } } } return ret; } int main() { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); ll n, m; cin >> n >> m; vll a(m), b(m), c(m); rep(i, m){ cin >> a[i] >> b[i] >> c[i]; a[i]--; b[i]--; } GraphL<> g1(n); rep(i, m){ if(c[i] == 1){ g1.add_edge(a[i], b[i]); g1.add_edge(b[i], a[i]); } } vll col(n, 0); vector visited(n, false); auto dfs = [&](auto& Self, int node, int cc, int p = -1) -> void{ visited[node] = true; col[node] = cc; for(auto&& e: g1[node]){ if(!visited[e.to]){ Self(Self, e.to, cc, node); }else if(e.to != p){ Pr(1); } } }; ll cc = 0; rep(i, n){ if(!visited[i]){ dfs(dfs, i, cc); cc++; } } GraphL<> g2(cc); auto dfs2 = [&](auto& Self, int node, int p = -1) -> void{ visited[node] = true; for(auto&& e: g2[node]){ if(!visited[e.to]){ Self(Self, e.to); }else if(e.to != p){ Pr(1); } } }; rep(i, m){ if(c[i] == 2){ g2.add_edge(col[a[i]], col[b[i]]); } } fill(ALL(visited), 0); dump(g2); Pr(SZ(TopologicalSort(g2)) == 0); }