#include <bits/stdc++.h> // #ifndef ONLINE_JUDGE // #include </home/vamh/Documents/cp/idkman/debug.h> // #endif //ONLINE_JUDGE #define ll long long #define all(x) x.begin(), x.end() #define Neco "Neco" #define resp(x) sort(all(x)), x.resize(unique(all(x)) - x.begin()) #define getbit(x,i) ((x >> i)&1) #define _left id * 2, l, mid #define _right id * 2 + 1, mid + 1, r #define cntbit(x) __builtin_popcountll(x) #define fi(i, a, b) for(int i = a; i <= b; i++) #define fid(i, a, b) for(int i = a; i >= b; i--) #define maxn (int) (2e5 + 7) using namespace std; const ll mod = 1e9 + 7; //972663749 const ll base = 911382323; mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); ll GetRandom(ll l, ll r) { return uniform_int_distribution<ll> (l, r)(rng); } void Input(); void reset(); int n, m; vector<int> edges[maxn], g[maxn]; int cha[maxn][18], In[maxn], Out[maxn], Time; int S[maxn], T[maxn], h[maxn]; void pre_dfs(int u, int par) { In[u] = ++Time; for(int v : edges[u]) if(v != par) { cha[v][0] = u, h[v] = h[u] + 1; fi(i, 1, 17) cha[v][i] = cha[cha[v][i - 1]][i - 1]; pre_dfs(v, u); } Out[u] = Time; } int lca(int u, int v) { if(h[u] < h[v]) swap(u, v); fid(i, 17, 0) if(h[u] - (1 << i) >= h[v]) u = cha[u][i]; if(u == v) return u; fid(i, 17, 0) if(cha[u][i] != cha[v][i]) { u = cha[u][i], v = cha[v][i]; } return cha[u][0]; } bool isInPath(int k, int u, int v) { auto isInSubtree = [](int u, int r) { return In[r] <= In[u] && In[u] <= Out[r]; }; int p = lca(u, v); return (isInSubtree(k, p) && isInSubtree(u, k)) || (isInSubtree(k, p) && isInSubtree(v, k)); } bool topoSort() { vector<int> deg(n + 1, 0); fi(i, 1, n) for(int v : g[i]) deg[v] ++; queue<int> q; fi(i, 1, n) if(!deg[i]) q.push(i); while(!q.empty()) { int u = q.front(); q.pop(); for(int v : g[u]) if(--deg[v] == 0) { q.push(v); } } return *max_element(all(deg)) == 0; } void solve() { Input(); if(m > 500) return; Time = 0; pre_dfs(1, 0); fi(i, 1, m) fi(j, 1, m) if(i != j) { if(isInPath(S[j], S[i], T[i])) g[j].push_back(i); if(isInPath(T[j], S[i], T[i])) g[i].push_back(j); } if(topoSort()) cout << "Yes\n"; else cout << "No\n"; reset(); } void Input() { cin >> n; fi(i, 1, n - 1) { int x, y; cin >> x >> y; edges[x].push_back(y); edges[y].push_back(x); } cin >> m; fi(i, 1, m) cin >> S[i] >> T[i]; } void reset() { fi(i, 1, n) edges[i].clear(), g[i].clear(); fi(i, 1, n) fi(j, 0, 17) cha[i][j] = 0; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); if(fopen(Neco".inp", "r")) { freopen(Neco".inp", "r", stdin); freopen(Neco".out", "w", stdout); } int nTest = 1; cin >> nTest; while(nTest--) { solve(); } return 0; }

jail.cpp: In function 'int main()':
jail.cpp:127:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  127 |         freopen(Neco".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
jail.cpp:128:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         freopen(Neco".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~