#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define X first #define Y second #define pb push_back #define rep(X,Y) for (int X = 0;X < (int)(Y);++X) #define reps(X,S,Y) for (int X = (int)(S);X < (int)(Y);++X) #define rrep(X,Y) for (int X = (int)(Y)-1;X >=0;--X) #define rreps(X,S,Y) for (int X = (int)(Y)-1;X >= (int)(S);--X) #define repe(X,Y) for (X = 0;X < (Y);++X) #define peat(X,Y) for (;X < (Y);++X) #define all(X) X.begin(),X.end() #define rall(X) X.rbegin(),X.rend() #define eb emplace_back #define UNIQUE(X) X.erase(unique(all(X)),X.end()) #define Endl endl #define NL <<"\n" #define cauto const auto using namespace std; using ll=long long; using pii=pair; using pll=pair; template using vv=vector>; template inline bool MX(T &l,const T &r){return l inline bool MN(T &l,const T &r){return l>r?l=r,1:0;} //#undef NUIP #ifdef NUIP #include "benri.h" #else #define out(args...) #endif void ouT(ll x,int d=3){auto re=to_string(x);if((int)re.size()>d) re=x>0?"oo":"-oo";cout<vector table(int n, T v){ return vector(n, v);} template auto table(int n, Args... args){auto val = table(args...); return vector(n, move(val));} #endif template pair operator+(const pair &p,const pair &q){ return {p.X+q.X,p.Y+q.Y};} template pair& operator+=(pair &p,const pair &q){ p.X+=q.X; p.Y+=q.Y; return p;} template pair operator-(const pair &p,const pair &q){ return {p.X-q.X,p.Y-q.Y};} template pair& operator-=(pair &p,const pair &q){ p.X-=q.X; p.Y-=q.Y; return p;} template istream& operator>>(istream &is, pair &p){ is>>p.X>>p.Y; return is;} template T read(){ T re; cin>>re; return re;} template T read(const T &dec){ T re; cin>>re; return re-dec;} template vector readV(const int sz){ vector re(sz); for(auto &x:re) x=read(); return re;} template vector readV(const int sz, const T &dec){ vector re(sz); for(auto &x:re) x=read(dec); return re;} vv readG(const int &n,const int &m){ vv g(n); rep(_,m){ cauto a=read(1),b=read(1); g[a].pb(b); g[b].pb(a);} return g;} vv readG(const int &n){ return readG(n,n-1);} vv readD(const int &n,const int &m){ vv g(n); rep(_,m){ cauto a=read(1),b=read(1); g[a].pb(b); } return g;} vv readD(const int &n){ return readD(n,n-1);} template vv> readG(const int &n,const int &m){ vv> g(n); rep(_,m){ cauto a=read(1),b=read(1); cauto c=read(); g[a].eb(b,c); g[b].eb(a,c);} return g;} template vv> readG(const int &n){ return readG(n,n-1);} template vv> readD(const int &n,const int &m){ vv> g(n); rep(_,m){ cauto a=read(1),b=read(1); cauto c=read(); g[a].eb(b,c); } return g;} template vv> readD(const int &n){ return readD(n,n-1);} #ifdef __cpp_deduction_guides template vector readT(int n, T v){ return readV(n,v);} template auto readT(int n, Args... args){ vector re(1,readT(args...));rep(_,n-1) re.eb(readT(args...)); return re;} template void read_tuple_impl(istream &is, Tuple& t, index_sequence){((is >> get(t)), ...);} template auto& operator>>(istream &is, tuple& t){ read_tuple_impl(is, t, index_sequence_for{}); return is;} template bool erase(multiset &st, const T &v){if(cauto it=st.find(v); it==st.end()) return false; else{ st.erase(it); return true;}} #endif #ifdef __cpp_init_captures template void addadd(T& t1, const T& t2, integer_sequence){ cauto l = { (get(t1) += get(t2), 0)... }; (void)l;} template tuple& operator += (tuple& lhs, const tuple& rhs){ addadd(lhs, rhs, index_sequence_for{}); return lhs;} template tuple operator +(tuple lhs, const tuple& rhs){ return lhs += rhs;} template void subsub(T& t1, const T& t2, integer_sequence){ cauto l = { (get(t1) -= get(t2), 0)... }; (void)l;} template tuple& operator -= (tuple& lhs, const tuple& rhs){ subsub(lhs, rhs, index_sequence_for{}); return lhs;} template tuple operator - (tuple lhs, const tuple& rhs){ return lhs -= rhs;} #endif #ifdef NUIP #define TT cauto TTT=read();rep(kase,TTT)if(cerr<<"Case #"<friend vectoroperator-(vectora,sorted_impl){sort(all(a));return a;}friend string operator-(string a,sorted_impl){sort(all(a));return a;}}sorted;struct reversed_impl{templatefriend vectoroperator-(vector a,reversed_impl){reverse(all(a));return a;}friend string operator-(string a,reversed_impl){reverse(all(a));return a;}}reversed;struct distinct_impl{templatefriend vectoroperator-(vector a,distinct_impl){sort(all(a));UNIQUE(a);return a;}}distinct;templatestruct sortedWith{const S f;sortedWith(const S &f):f(f){}templatefriend vectoroperator-(vector a,const sortedWith&b){sort(all(a),[&](cauto&i,cauto&j){return b.f(i)int operator/(const T&v,const vector&vs){return lower_bound(all(vs),v)-vs.begin();} vector Inds(const int n){vector inds(n);iota(all(inds),0);return inds;} const ll MOD=1e9+7; //998244353; typedef vv Graph; class Lca{ public: vector dep,cld; vector wdep; vv par; const int LOGN=20; int weighted; vv wei; void dfs(const Graph &g,int root){ int n=g.size(); vector vst(n); stack st; st.push(root); while(!st.empty()){ int v=st.top(); st.pop(); if(vst[v]==1){ vst[v]=2; rep(i,g[v].size())if(g[v][i]!=par[v][0]) cld[v]+=cld[g[v][i]]+1; }else if(vst[v]==0){ st.push(v); vst[v]=1; rep(i,g[v].size())if(!vst[g[v][i]]){ dep[g[v][i]]=dep[v]+1; wdep[g[v][i]]=wdep[v]+(weighted?wei[v][i]:1); par[g[v][i]][0]=v; st.push(g[v][i]); } } } } Lca(const Graph &g):weighted(0){ int n=g.size(); par.resize(n,vector(LOGN,-1)); dep.resize(n); wdep.resize(n); cld.resize(n); dfs(g,0); rep(i,LOGN-1)rep(v,n) par[v][i+1]=par[v][i]<0?-1:par[par[v][i]][i]; } Lca(const vv &h):weighted(1){ int n=h.size(); vv g(n); wei.resize(n); rep(i,n) for(pii x:h[i]){ g[i].pb(x.X); wei[i].pb(x.Y); } par.resize(n,vector(LOGN,-1)); dep.resize(n); wdep.resize(n); cld.resize(n); dfs(g,0); rep(i,LOGN-1)rep(v,n) par[v][i+1]=par[v][i]<0?-1:par[par[v][i]][i]; } int anc(int v,int n){ rep(i,LOGN)if(n>>i&1) if((v=par[v][i])<0)break; return v; } int LCA(int v,int w){ if(dep[v]>dep[w]) swap(v,w); w=anc(w,dep[w]-dep[v]); rrep(i,LOGN) if(par[v][i]!=par[w][i]){ v=par[v][i]; w=par[w][i]; } return v==w?v:par[v][0]; } ll dist(int v,int w){return wdep[v]+wdep[w]-2*wdep[LCA(v,w)];} }; int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout< szs(n,1); { cauto dfs= [&](auto &&dfs, int v, int p)->int{ for(cauto &u:g[v])if(u!=p) szs[v]+=dfs(dfs,u,v); return szs[v]; }; dfs(dfs,0,-1); } for(cauto &[u,v]:qs){ cauto d=h.dist(u,v); if(d%2){ cout<<0 NL; continue; }else if(h.dep[u]==h.dep[v]){ cauto pu=h.anc(u,d/2-1); cauto pv=h.anc(v,d/2-1); cout<h.dep[v]?u:v); cauto b=h.anc(c,d/2-1); cauto a=h.par[b][0]; cout<