#include #include #include #include #include #include #include using namespace atcoder; using namespace std; #define ll long long #define P pair #define Pl pair,ll> ostream& operator<<(ostream& os,const P& a){ return os<& a){ for(ll i:a){ os<>& a){ for(vector i:a){ for(int j:i){ os<& a){ for(P i:a){ os<>N; dsu uf(N); vector>to(N); for(int i=0;i>A>>B; uf.merge(A-1,B-1); to.at(A-1).push_back({B-1,i}); if(A!=B){ to.at(B-1).push_back({A-1,i}); } } vector seen(N); vectorans(N,-1); vector> groups=uf.groups(); for(vector linked:groups){ bool is_cycle=true; ll root=-1,cycle_cnt=0; for(int point:linked){ ll link_size=to.at(point).size(); for(ll k=0;k1){ //自己ループが2つ以上 printf("No\n"); cerr<<"1\n"; return 0; } if(is_cycle){ ll next_point=-1; deque

que; que.push_back({linked.at(0),-1}); while(!que.empty()){ P q=que.back(); que.pop_back(); for(P j:to.at(q.first)){ if(j.second==q.second)continue; if(seen.at(j.first)){ root=j.first; next_point=q.first; ans.at(j.second)=root+1; que.clear(); break; } que.push_back({j.first,j.second}); } seen.at(q.first)=1; } if(next_point==-1){ //頂点が1つのとき、かつ辺の数が0のとき printf("No\n"); cerr<<"2\n"; return 0; } } dequedq; dq.push_back(root); while(!dq.empty()){ ll q=dq.back();dq.pop_back(); for(P j:to.at(q)){ if(ans.at(j.second)==-1){ ans.at(j.second)=j.first+1; dq.push_back(j.first); } } } } for(ll i:ans){ if(i==-1){ //塗れていないとき printf("No\n"); cerr<<"3\n"; return 0; } } cout<<"Yes\n"; cout<