이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
//Challenge: Accepted
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
while (l != r) cout << *l << " ", l++;
cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 120005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
vector<int> adj[maxn], g[maxn];
set<int> path[maxn];
int anc[18][maxn], dep[maxn], deg[maxn];
pii ed[maxn];
void dfs(int n, int par, int d) {
anc[0][n] = par;
dep[n] = d;
for (int v:adj[n]) {
if (v != par) {
dfs(v, n, d + 1);
}
}
}
int main() {
io
int T;
cin >> T;
while (T--) {
int n;
cin >> n;
for (int i = 1;i <= n;i++) {
adj[i].clear();
g[i].clear();
path[i].clear();
deg[i] = 0;
}
for (int i = 0;i < n - 1;i++) {
int u,v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1, 0, 0);
int m;
cin >> m;
auto addedge = [&] (int u, int v) {
//debug("edge", u, v);
g[u].push_back(v);
deg[v]++;
};
for (int i = 1;i <= m;i++) {
int u, v;
cin >> u >> v;
int tu = u, tv = v;
while (tu != tv) {
if (dep[tu] < dep[tv]) swap(tu, tv);
path[i].insert(tu);
tu = anc[0][tu];
}
path[i].insert(tu);
ed[i] = {u, v};
}
for (int i = 1;i <= m;i++) {
for (int j = i+1;j <= m;j++) {
if (path[i].find(ed[j].ff) != path[i].end()) addedge(j, i);
if (path[i].find(ed[j].ss) != path[i].end()) addedge(i, j);
if (path[j].find(ed[i].ff) != path[j].end()) addedge(i, j);
if (path[j].find(ed[i].ss) != path[j].end()) addedge(j, i);
}
}
queue<int> que;
for (int i = 1;i <= n;i++) {
if (deg[i] == 0) que.push(i);
}
int cnt = 0;
while (que.size()) {
int cur = que.front();que.pop();
cnt++;
for (int v:g[cur]) {
if (--deg[v] == 0) que.push(v);
}
}
cout << (cnt == n ? "Yes" : "No") << "\n";
}
}
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