#include using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- class SCC { public: static const int MV = 2025000; vector > SC; int NV,GR[MV]; private: vector E[MV], RE[MV], NUM; int vis[MV]; public: void init(int NV) { this->NV=NV; for(int i=0;i=0;i--) if(!vis[NUM[i]]){ SC[c].clear(); revdfs(NUM[i],c); sort(SC[c].begin(),SC[c].end()); c++; } SC.resize(c); } }; template class UF { public: vector par,rank; UF() {rank=vector(um,0); for(int i=0;irank[y]) return par[x]=y; rank[x]+=rank[x]==rank[y]; return par[y]=x; } }; UF<500000> uf; SCC scc; int N,M; vector> BE; vector E[101010]; void solve() { int i,j,k,l,r,x,y; string s; cin>>N>>M; scc.init(N); FOR(i,M) { cin>>x>>y>>j; if(j==1) { if(uf[x-1]==uf[y-1]) return _P("Yes\n"); uf(x-1,y-1); } else { BE.push_back({x-1,y-1}); } } FORR(e,BE) { if(uf[e.first]==uf[e.second]) return _P("Yes\n"); scc.add_edge(uf[e.first],uf[e.second]); } scc.scc(); if(scc.SC.size()!=N) return _P("Yes\n"); _P("No\n"); } int main(int argc,char** argv){ string s;int i; if(argc==1) ios::sync_with_stdio(false), cin.tie(0); FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin); cout.tie(0); solve(); return 0; }