#include using namespace std; typedef signed long long ll; #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 FORR2(x,y,arr) for(auto& [x,y]:arr) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) template bool chmax(T &a, const T &b) { if(a bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;} //------------------------------------------------------- int N; int A[202020],B[202020]; set S[202020]; int E[202020]; void dfs(int cur) { while(S[cur].size()) { int e=*S[cur].begin(); E[cur]=e; S[cur].erase(e); S[e].erase(cur); dfs(e); } } void solve() { int i,j,k,l,r,x,y; string s; cin>>N; FOR(i,N) { cin>>A[i]>>B[i]; A[i]--,B[i]--; S[A[i]].insert(B[i]); S[B[i]].insert(A[i]); } queue Q; FOR(i,N) if(S[i].size()==1) Q.push(i); while(Q.size()) { x=Q.front(); Q.pop(); y=*S[x].begin(); E[x]=y; S[x].erase(y); S[y].erase(x); if(S[y].size()==1) Q.push(y); } FOR(i,N) if(S[i].size()) dfs(i); FOR(i,N) { if(E[A[i]]==B[i]) cout<<"->"<