//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 #include #include #include #include using namespace std; // typedef //------------------------------------------ typedef long long LL; typedef vector VI; typedef vector VB; typedef vector VC; typedef vector VD; typedef vector VS; typedef vector VLL; typedef vector VVI; typedef vector VVB; typedef vector VVS; typedef vector VVLL; typedef vector VVVI; typedef vector VVVLL; typedef pair PII; typedef pair PLL; typedef pair PIS; typedef pair PSI; typedef pair PSS; typedef vector VPII; typedef vector VPLL; typedef vector VVPII; typedef vector VVPLL; typedef vector VVS; typedef map MII; typedef map MLL; typedef map MSI; typedef map MIS; // container util //------------------------------------------ #define ALL(a) (a).begin(),(a).end() #define SZ(a) int((a).size()) #define EACH(i, arr) for(typeof((arr).begin()) i=(arr).begin(); i!=(arr).end(); ++i) #define EXIST(str, e) ((str).find(e)!=(str).end()) #define COUNT(arr, v) count((arr).begin(), (arr).end(), v) #define SEARCH(v, w) search((v).begin(), (v).end(), (w).begin(), (w).end()) #define SORT(c) sort((c).begin(),(c).end()) #define RSORT(c) sort((c).rbegin(),(c).rend()) #define REVERSE(c) reverse((c).begin(), (c).end()) #define ROTATE_LEFT(arr, c) rotate((arr).begin(), (arr).begin()+(c), (arr).end()) #define ROTATE_RIGHT(arr, c) rotate((arr).rbegin(), (arr).rbegin() + (c), (arr).rend()) #define SUMI(arr) accumulate((arr).begin(), (arr).end(), 0) #define SUMD(arr) accumulate((arr).begin(), (arr).end(), 0.) #define SUMLL(arr) accumulate((arr).begin(), (arr).end(), 0LL) #define MULD(arr) accumulate((arr).begin(), (arr).end(), 1., multiplies()) #define UB(arr, n) upper_bound((arr).begin(), (arr).end(), n) #define LB(arr, n) lower_bound((arr).begin(), (arr).end(), n) #define PB push_back #define MP make_pair #define ft first #define sd second // input output //------------------------------------------ #define GL(s) getline(cin, (s)) #define INIT() std::ios::sync_with_stdio(false);std::cin.tie(0) #define OUT(d) std::cout<<(d) #define OUT_L(d) std::cout<<(d)< istream &operator>>(istream &in, pair &p) { in >> p.first >> p.second; return in; } template istream &operator>>(istream &in, vector &v) { for (auto &x: v) in >> x; return in; } template ostream &operator<<(ostream &out, const std::pair &p) { out << "[" << p.first << ", " << p.second << "]" << "\n"; return out; } template inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return true; } return false; } //repetition //------------------------------------------ #define FOR(i, a, b) for(int i=(a);i<(b);++i) #define RFOR(i, a, b) for(int i=(b)-1;i>=(a);--i) #define REP(i, n) FOR(i,0,n) #define RREP(i, n) for(int i = n-1;i >= 0;i--) #define FORLL(i, a, b) for(LL i=LL(a);i=LL(a);--i) #define REPLL(i, n) for(LL i=0;i=0;--i) #define FOREACH(x, arr) for(auto &(x) : (arr)) void CaseOutput(int p) { printf("Case #%d: ", p); } //------------------------------------------ //------------------------------------------ struct UnionFind { vector par; vector sizes; UnionFind(int n) : par(n), sizes(n, 1) { for (int i = 0; i < n; i++) { par[i] = i; } } int find(int x) { return x == par[x] ? x : par[x] = find(par[x]); } bool unite(int x, int y) { x = find(x); y = find(y); if (x == y) return false; if (sizes[x] < sizes[y]) swap(x, y); par[y] = x; sizes[x] += sizes[y]; return true; } bool same(int x, int y) { return find(x) == find(y); } int get_size(int x) { return sizes[find(x)]; } bool all_same() { bool good = true; for (int i = 0, n = par.size(); i < n; i++) if (find(0) != find(i)) good = false; return good; } int get_connectivity() { set s; for (int i = 0, n = par.size(); i < n; i++) s.insert(find(i)); return s.size(); } }; template struct Edge { int from, to; T cost; Edge(int from, int to, T cost) : from(from), to(to), cost(cost) {} explicit operator int() const { return to; } }; template using Edges = vector>; template using WeightedGraph = vector>; using UnWeightedGraph = vector>; template using DistMatrix = vector>; struct GraphAdapter { template static UnWeightedGraph to_unweighted_graph(const WeightedGraph &origin) { int V = origin.size(); UnWeightedGraph graph(V); for (int i = 0; i < V; i++) for (auto &e: origin[i]) graph[i].push_back((int) e); return graph; } static WeightedGraph to_weighted_graph(const UnWeightedGraph &origin) { int V = origin.size(); WeightedGraph graph(V); for (int i = 0; i < V; i++) for (auto to: origin[i]) graph[i].push_back({i, to, 1}); return graph; } template static DistMatrix to_dist_matrix(const WeightedGraph &origin, T INF) { int V = origin.size(); DistMatrix matrix(V, vector(V, INF)); for (int i = 0; i < V; i++) for (auto &e:origin[i]) matrix[i][e.to] = e.cost; for (int i = 0; i < V; i++) matrix[i][i] = 0; return matrix; } }; int dfs(int ori, int v, UnWeightedGraph &G, vector& visited) { visited[v] = true; int ok = 0; for (auto to: G[v]) { if (to == ori) return 1; if (visited[to]) continue; ok |= dfs(ori, to, G, visited); } return ok; } int main() { int N, M; cin >> N >> M; vector a(M), b(M), c(M); REP(i, M) cin >> a[i] >> b[i] >> c[i], a[i]--, b[i]--; UnionFind UF(N); REP(i, M) { if (c[i] == 1) { if (UF.same(a[i], b[i])) { cout << "Yes" << endl; return 0; } UF.unite(a[i], b[i]); } } UnWeightedGraph G(N); REP(i, M) { if (c[i] == 2) { int x = UF.find(a[i]); int y = UF.find(b[i]); G[x].push_back(y); } } int ans = 0; vector visited(N, false); for (int i = 0; i < N; i++) ans |= dfs(i, i, G, visited); if (ans) Yes(); else No(); }